I recently found out that my guild master, Squinky, is a renowned SPriest and has an amazing thread on single button macros that sustain all dots and maximize dps. He helped me start this macro and inspired me to take it to the depth he has. I'll start by saying this: Yes, it's possible. I'll add this, however: It isn't easy and it takes time. It has to be carefully fine tuned to your haste and crit chance. My haste is currently 1356, 1132 crit(39.21% self-buffed and LotP). Also consider that I am hit capped as well as soft expertise capped.
Considering that my crit is as high as it is, I can assume that 1 out of 4 abilities will crit, thus guaranteeing I will get 5 points every time I go to cast Rip. I know sometimes Clearcasting will kick in a ton and I'll power through some abilities and have some idle time before the next Tiger's Fury is off cooldown which can easily be filled with a Shred or two. I know some times Clearcasting won't proc at all and the macro will drag along but all the buffs/debuffs will stay up. If done properly(not just mashing the button but waiting half about a second or so between abilities), Rip will be off the target a total of 3 seconds but always be applied during Tiger's Fury(therein making it do more damage), Rake will never be off the target for any longer than a second, and Savage Roar will always be up. But remember, this must be fine tuned: some abilities may need to be removed/added to properly compensate for your lack/abundance of haste. I will hopefully get the formula down soon so I can have several exact macros that will work for any particular level of haste.
This macro is intended for the T11 4-piece(my T12 4-piece is part of my tank set). You use the first one until Cower is cast or you can do other things like Nature's Grasp to get your attention or any Bear Form ability to lock the macro up so you're reminded to change to the sustaining macro. I'm currently working on one that includes Berserk from the start that will eventually go to the sustaining macro as well as ones for Bloodlust, already having your T11 4-piece macro active, having a certain amount of talent points already active on the target, and so on. For those of you using your T12 4-piece the second and third Mangle can be replaced with Shred, as well as every other Mangle being replaced by Shred.
I'll say this one last time - If the macro doesn't work perfectly don't get angry and blame me for being a /facepalm. To have this properly work, it's going to need fine tuning unless you have gear mirroring mine as well as the exact same enchants, gemming and reforging. Given a little work, this macro is a dps improvement. To use these macros you will need an addon that allows you to make macros that are longer than 255 characters.
/use 13
/use 14
/castsequence reset=target Faerie Fire (Feral), Mangle(Cat Form), Savage Roar, Rake, Mangle(Cat Form), Tiger's Fury, Mangle(Cat Form), Rake, Rip, Shred, Shred, Savage Roar, Shred, Shred, Rake, Ferocious Bite, Mangle(Cat Form), Mangle(Cat Form), Shred, Tiger's Fury, Rake, Rip, Shred, Shred, Shred, Savage Roar, Shred, Rake, Mangle(Cat Form), Ferocious Bite, Shred, Shred, Cower(Cat Form)
/script UIErrorsFrame:Clear()
This macro will sustain all the buffs as long as you go into it straight from the previous macro or have at least 4 combo points active on your current target. It will not, however, give you your T11 4-piece stacks until the second Tiger's Fury unless it's already active. The easiest way to fix that is by using Mangle at least once but ideally twice before using the macro.
/use 13
/use 14
/castsequence reset=target Tiger's Fury, Rake, Rip, Shred, Mangle(Cat Form), Shred, Savage Roar, Shred, Rake, Mangle(Cat Form), Shred, Ferocious Bite, Shred, Shred, Shred, Shred,
/script UIErrorsFrame:Clear()
I'm working on the Berserk macro now that includes Feral Charge/Ravage from the start. Hopefully I can get it working soon.