Here's at least one Kinect hacker, who also wants to buy quality clothing. It'd be pretty cool to have an app that automatically takes your measurements. Of course, you'd have to be wearing tight clothing for it to be accurate.
Edit: it might also be possible to get a rough personal preview of a shirt using skeleton tracking.
As for camera owners overlapping with shirt owners, there are millions of Kinect cameras out there hooked up to Xboxes, and as people start buying them for PCs, that number will grow.
If it ends up making sense, I think you should do it.
"Of course, you'd have to be wearing tight clothing for it to be accurate."
Effectively-no clothing would be much better. It's not like a human is looking you over. You'd also need to hold a known calibration image, too. I'm still not sure you could do it even then to the requisite accuracy, that's asking an awful lot, but maybe. Would take some clever work and a lot of testing.
