Funny you should say that, but I bought a suit at Asda a few months ago, which is the UK equivalent of Walmart, and it is owned by Walmart. I bought it as a temporary fix because I was changing size. However thr 34 inch trousers I bought with the suit would not fit me, so I had to go back and but a pair of 36" ones as well (they were cheap enough!). I'll just measure them now... and sure enough the 36" ones are 36.5", which is near enough. I think your theory is correct.

Anyway eventually they will be too big for me, but the 34s will extend the life of the suit a little longer.

(edit) Oh and by the way I didn't try them on because I was buying lots of other 34s at the time and they all fitted. In retrospect now I know the Walmart ones were the only ones sized correctly. But I am not sure that is the case after finding this... http://www.3fatchicks.com/forum/showthread.php?t=134047