Real estate or architecture?
They're kinda the same thing, kinda not. If you're shooting architecture professionally, a TS lens would be a really good idea. However, if this is just real estate shooting (walking around/handheld, etc) I think a 17-40L would be a better idea.
The 10-22 on a crop body is the equivalent to the 16-35 on a FF. I've owned all three lenses, 10-22, 16-35 and 17-40 and they all feel about the same in the focal length department. I like the IQ of the 17-40 best, but the 16-35 is pretty much identical. The only thing I'd think about is how much handheld inside shooting you'd be doing. This is the one case in which I *might* choose the 16-35 over the 17-40, however, the 5D3 does so a remarkably well in low light, I feel like the extra stop isn't a deal breaker for me.
Lastly, like it was suggested earlier, the Canon 14L would be an awesome lens to shoot with as well, especially indoors. It does really well with distortion and has the f/2.8, overall great lens.