la police gear is clearing out their 5.11 digital camo vests, a medium is $17.99 and a small is just $7.99.
i'm a medium framed fella and I ordered the small (couldn't resist the price) and I just got it yesterday and it fits perfectly. So the medium should (should is a key word) fit a large person as well. (heck if not you could just e-bay it and get alot more money for it).
http://www.lapolicegear.com/5tadicave.html