Bosses that are Solotankable:
Immerseus: Yes
Protectors: Yes
Norushen: Yes
Sha: Yes
Galakras: Yes (But really really annoying and sub-optimal)
Juggernaut: Yes
Shamans: No*
Nazgrim: Yes**
Malkorok: Yes***
Spoils: Yes****
Thok: Yes
Siegecrafter: Yes*****
Paragons: Yes*******
Garrosh: Yes*******
*I have yet to figure out a way to do it, but if the raid had enough dps to burn the bosses down before your stacks get too high it "may" be possible.
**Nazgrims Sunder can't reduce your armor below 0%. You'll spawn Ravagers on each cast due to how much rage he'll get, and you'll take a hell of a beating, but it's possible.
***Malkork is one that most people would assume is undoable due to the tank stacks. In P1 you'll take all stacks, which isn't all too hard if you rotate cds. In P2 you'll need the entire raid to stack up and soak the cleave with you, and you'll also need strong raid cds while this is going. Your stacks will reset before the next P1 and you'll just do the same thing again.
****The way to do Spoils while solotanking is the same way that some 10man guilds did it. You send the tank + some real strong dps to one side, and you open like a maniac so that you're done as fast as possible. On the other side you have a few dps that will mainly kill sparks, but they can also open up a few small ones just to get some dps going there as well. Once you've finished off the big ones, and you're close to capping on energy you need to send over your tank and a good amount of dps as well to burn the second side as well before the timer runs out, you'll most likely need a lot of warlocks and monks who can teleport up without using the chain. If you finish the second room before the timer runs out you just do the same thing again, and hope you'll make it in time.
*****The tank debuff on Siegecrafter caps at 10stacks. You can easily survive the application of a 10stack debuff with a strong barrier + a strong cooldown. You can literally one-shot the shredder with those amounts of stacks + the 600-800k vengeance you'll have while tanking both of them.
******Paragons is most likely the hardest one to solo, as it requires a lot of help from your raid.
On the pull your raid need to push down Swarmkeeper in order for the bloods to go on him, then pop Blood Lust and zerg down Bloodseeker. You'll most likely need to rotate all of your personal cds and externals in order to survive the Bloodseeker/Disector Combo, as you can hardly use any Active Mitigation, and Bloodseeker applies a stacking debuff that increases the damage you take from Disector.
Once Bloodseeker is dead you'll need a paladin to HoP you and then instantly cancelaura it to get rid of your Hewn stacks. This phase is just like it normally would be, with the exception that you're tanking both bosses.
Once Disector is dead you'll need to start cleaving down Prime and Locust just like normal. The bleed that is applied to you when Prime dose his frontal cleave will stacking up to dangerous levels after a short while. At that point you'll need to be HoP'ed again in order to reset the stacks. Try to wait with this as long as possible so that the stacks can't stack up too high after you've reset them.
If you've managed to survive the Locus/Prime combo it's time to kill Swarmkeeper. This part is the same as it normally is.
When Poisoned Mind spawns you'll want to kill Locust. Due to you killing Locust at this point your raid will need to handle 2-3 of Catalysts, but they aren't gonna kill your raid.
Once Locust is dead you switch over to Poisoned Mind. The amount of raid damage that's going out is now really high, so you'll need to handle yourself a lot. Remember to dance so that you're not hit by Manipulators attacks as they are fully avoidable.
As Poisoned Mind dies you'll need a third and final HoP from a paladin to cleanse yourself from the debuff that he applies that increases the damage you take from Wind-Reaver. At this point what you kill depends on your raid. If your healers can handle the damage that the Fiery Lines are putting out then you should kill Manipulator. If your raid has a lot of range / people who can negate the Kunchongs focus then you should kill Lucid.
Once you've finished off both of those you're left with Wind-Reaver, and he's a piece of cake to finish off.
*******In order to fully solo tank this fight you'll need to kill off the adds that spawns from Corrupted Whirl rather than kiting them. This ain't really that hard, and if you want to whore some extra vengeance I'd recommend that you have 3-4adds in melee who you cleave down.
PS: I think that the * system would have worked better if I didn't have 7fights I wanted to explain a little more.