What is the color space on the T3i? Is it 4:2:0? I have searched for 2 hours trying to find some conclusive evidence, but all I can find is for the 7D and T2i.

This is what I've determined:

5Dm2: 4:2:0
7D: 4:2:0
T2i: 4:2:0
T3i: ??

Is the above correct? What is the T3i? Do you have a link to the specs? Someone told me the T3i is 4:2:2, but I'm having a hard time swallowing that one.

It can't be 4.2.2. That colorspace isn't supported in the standard for the codec used on the Canon DSLRs.

It can only be 4.2.0.