[ahlatimer]

Some companies are already doing that. True Fit is the one I've seen when shopping for an Arc'teryx jacket. I think I've seen it elsewhere, but I couldn't tell you where.

It wasn't particularly accurate, in my experience. It told me to get a medium when a small actually fit better, but it also didn't have my favorite shirt in its database, so I had to go with something that had a decent but worse fit as a comparison.