Longshot request 29.5 x 29 wheels

I'm in the market for two wheels/rims on which I can mount 29.5 x 29 tires that I already own. The configuration of the wheel doesn't matter; that is to say that the wheels can be from the rear of a scraper or from a 988 axle with the planetary ring gears mounted in them (even better if I could get the whole axle!). Also, it doesn't matter if old tires are still on them or if the wheels have been removed from a machine that was on a military A10-Warthog bomb range-id be happy just to have SOMETHING I can work with or repair.
I can find the tires aplenty, but the rims/wheels have been scarce. ANY information that would aide in locating two wheels would be greatly appreciated.
Btw, I'm located in south central Missouri but have a couple weeks of vacation coming up and can travel within the contiguous United States.

Thanks in advance!

http://www.machinerytrader.com/list/dismantledsearch.aspx?ETID=3&Manu=CATERPILLAR&Mdltxt=621B&mdlx=exact

Here's a bunch of dismantled machines that will have those size wheels.

Thanks d9gdon!!

Excellent advice! There are even some that aren't too far away from me.
VERY much appreciated!