I know this is a little late in the content level, but I put it together for a new character I was leveling so I thought I'd share it for anyone else who would be interested. Let me know if there are any mistakes. Thanks.
(More information on the factions is available in my rep guide)
There are three tiers of gear available from Cataclysm factions after reaching a certain level of reputation. This guide lays out the items available in order to help build the "quickest" means of acquiring them. Because you can not get reputation/commendations with the Tol Barad factions until level 85, I've put them in a separate section.
Rare gear of i333 level requires Honored reputation with the faction and a minimum of level 83.
Helm of Temperance, Earthen Ring
Gloves of Aetherial Rumors, Wildhammer Clan or Bone Fever Gloves, Dragonmaw Clan
Mages kind of get hosed that one of their level 83 items isn't available until they hit level 84. Getting Honored is relatively easy, however; once you complete the quest chain with Wildhammer or Dragonmaw you will be Honored.
Earthen Ring is a gimme, as questing in Deepholm (see below) once you hit 82 will get you Honored with them even if you never venture into Vash'jir.
Rare gear of i346 level required Revered reputation with the faction and a minimum of level 85.
Diamant's Ring of Temperance, Therazane
Cloak of Ancient Wisdom, Earthen Ring
Robes of Orsis, Ramkahen
The ring is relatively straightforward: questing in Deepholm will get you to Honored with Therazane, and it doesn't take many days of dailies to get Revered with them (nor to Exalted, for that matter). Since Shoulder enchants aren't BOA yet in Cataclysm, getting Exalted with them is pretty much a necessity if you want to raid. So no matter what, quest through Deepholm. You may want to use the Tabard of Therazane (although you can't until you've gotten to Friendly with them by questing), but as the other two items make clear, you'll need your tabard slot for other factions. Just complete Deepholm. You'll thank me later.
If you complete all the quests in Vash'jir, Deepholm, and Twilight Highlands, you will get close to Revered with the Earthen Ring. However, that requires completing all the quests in all three zones, and you may be 85 long before that happens. Sadly Earthen Ring has no daily quests so it's going to be Tabard time.
Completing the Ramkahen quests in Uldum (you can start at level 83; if you want to "rush" through it, avoid Harrison Jones as his quests do not give you Ramkahen rep) will get you to about 2000/12000 Honored before rep bonuses. There are then two easy dailies, but they don't give much, only about 400 rep before bonuses. So, yes, again it'll be Tabard time for Ramkahen.
Arcanum of Hyjal, requires level 85 and revered (also BOA)
If you quest through Mt Hyjal, you will be Revered when you finish. However, Hyjal is a long zone and if you want to maximize your Earthen Ring reputation you'll want to level in Vash'jir instead (despite the paltry ~3000-4000 rep you get there); since it's BOA all you need is one toon with the reputation to get it for you. Note: Before 4.0.6 the Arcanums required you to also have faction reputation to use; that is no longer the case.
Flamebloom Gloves, Earthen Ring
Desert Walker Sandals, Ramkahen
Lightning Flash Pendant, Wildhammer Clan or Yellow Smoke Pendant, Dragonmaw Clan
I don't know why mages luck out, but hunters only get two purples from faction rep. Harumph. Anyway, let's work from bottom to top.
After completing the faction quest chains in Twilight Highlands, you will be Honored with Wildhammer or Dragonmaw; you will also open up 5 dailies worth 1350 reputation before bonuses. The dailies in TH are nice because they're all concentrated in one area for the most part (unlike the Therazane dailies). It'll take awhile to get Exalted, but that's ok, at least you can make relatively rapid progress there just via the dailies, allowing you to ability to dedicate Tabard time to Earthen Ring and Ramkahen.
Who, of course, you'll need to, as nothing has changed from when you were aiming to get Revered with them. Which tabard you wear first (after you've gotten both to Revered) is really up to you; you may want to go with Ramkahen first, however, since the gear choices at i346 seem lighter for feet than hands (you can purchase Gloves of the Painless Midnight with Justice Points, but there are no boots you can purchase).
What it all means:
If you're looking to maximize the gear available to you from faction reputation, this is the path I would take:
1a) If you do not have a toon with Guardians of Hyjal revered reputation, level in Mt Hyjal until Revered. While you lose some reputation in Vash'jir, ultimately it's not much and you'll need that head enchant.
1b) If you do have another toon with Guardians of Hyjal, quest in Vash'jir until 82
2) Complete all the quests in Deepholm to unlock Therazane dailies and maximize Earthen Ring reputation; do this even if you ding 83 while there (if you don't ding 83 after doing all of them, go back to Vash'jir until you do)
3) In Uldum, start with the Ramkahen quest chain and ignore Harrison Jones until you've finished it. You should also be doing the Therazane dailies at this point.
4) Once you've completed the Ramkahen quest chain, if you're 84 go to Twilight Highlands, otherwise quest in Uldum (while continuing to do Therazane dailies) until 84.
5) At 84, quest all the way through Twilight Highlands. You will very likely ding 85 while doing so; if you have and you wish to start dungeon running for reputation you can, as long as you've opened up Wildhammer/Dragonmaw dailies.
If you're close to revered with Earthen Ring, I would wear their tabard first until Revered, then switch to Ramkahen until Exalted with them, then back to Earthen Ring. If you complete both to Exalted before you're Exalted with Wildhammer/Dragonmaw, then theirs is the next tabard to wear. If you're looking to increase your rep quickly, you may be better off chain-running normal 85s (Lost City, Halls of Origination, Grim Batol) instead of queueing for a random regular or heroic.
At 85 you'll run into an issue with dailies; you'll have wanted to start doing Tol Barad dailies (more on this below) and if you're lucky enough to be winning Tol Barad regularly, you won't have enough space to do Wildhammer/Dragonmaw and Therazane every day. Once you get Revered with Therazane, I would drop them for Wildhammer/Dragonmaw (at least you'll have a lesser shoulder enchant) since they have a nice purple waiting for you. Then once you're Exalted there, go back to Therazane.
If you have time to, you'll want to complete the quests in Uldum and Twilight Highlands. The first reason is if you don't complete Uldum, you won't unlock one of the Ramkahen dailies (which is unlocked during the Harrison Jones quest chain). The other reason is that the later quests in Uldum and Twilight Highlands award i325 and i333 items, so there will probably be upgrades available for you in there.
Tol Barad and You
Once you get to 85, Tol Barad opens up for you. Questing will get you rep with either Baradin's Wardens (Alliance) or Hellscream's Reach (Horde), and in addition to rep, you'll receive Commendations you can turn in for goodies. You can receive 6-7 Commendations a day completing 6 quests on Tol Barad Peninsula (the 7th comes because killing Tank nets you 2 if it's one of the dailies), and if your faction holds Tol Barad, you will open up 3 dailies and a rotating set of another 3 dailies. Because the rotating set varies after each victory, if your faction wins Tol Barad often, you may be able to complete up to 18 dailies in Tol Barad (this is why I mentioned dropping Therazane above). Besides the maximum 19 Commendations you can get from dailies, you also get 3 for completing the weekly "Win Tol Barad" quest, and another 3 for each victory you participate in.
For gear, you have essentially three tiers: i333 Trinket at Honored, i346 Weapon at Revered, and i359 Trinket at Exalted.
The first piece of gear, Baradin Footman's Tags, costs 40 commendations, is available at Honored, and is frankly probably not worth it unless you're really, really desperate for a Trinket upgrade (in which case you still may want to wait: see below).
At Revered and costing 85 commendations, you can pick up Insidious Staff. The nice thing about Revered is that you'll get there right about when you've received 85 commendations.
That's not the case for Exalted, though; you'll have the 125 commendations you need for Stump of Time a good while before getting Exalted with them. As a result, you may want to go with the Staff when you hit Revered instead of waiting for the trinket. It probably depends on your current gearing what your best option is.