Lee, check your local ag shops, some of them will build wheels for cheap. There is a local place here I've talked to about this. I think it was about $60 each if I provided the centers, then they would provide the outer rim to match my center and weld it in. This was for 16inch, not sure how the size increase would effect the price, but it is worth a try.
There is a catch, they essentially said I would have to swear to them that they are for off road use only, as they would NOT have a DOT stamp. If they knowingly built them for someone to use on the road, they are subject to a $10,000 fine.
