Any thoughts on putting 33x12.5 on stock 15x7 rims? I have seen it done befor, just wondering if anyone ever had issues with doing it?  

As a rule of thumb, 12.50 tires belong on a 8-10" rim. But some specific tires are recomended for use on a 8.5-10" rim.

So, for some tires maybe, for others probably not.

You might find the guys at the tire store unwilling to try. They seem to go by the book, you know, that Firestone thing!  

yep, no problems at all with running 12.l5's on 7" wheels.. I've even run 13.5's on 7" wheels.

if yer talking for a tj on stock steel wheels, you'll need 1" wheel spacers to keep the rear tires from getting the sidewalls ruined.

for the rubicon, the stock moab wheels are fine without spacers, though they are close.  

Perfectly fine to run 12.50's on 7" rims, but you may run into some rubbing issues where the tire's sidewall bulges away from the rim.  Could rub on LCAs.  Could change steering adjustment bolt on the knuckles, but you sacrifice turn radius.  I would recomend going to a 8" wide minimum.  10" is better.  Plus black steel wheels, like soft 8's and d widows, are cheap and strong!