Due to the 40 series wheels being wider than the standard maxx size tires the extra width is on the outside. This will give you some stability. I'm not sure of many if any 40 series wheels with a 1/2" offset. The moabs do not balloon as bad as you would think, but could use some balancing as link said. Taping them will get rid off any ballooning though. I think proline only has crome rims now. If you can find the wabash grab them. I think they are no longer making them. The Axial oversized are nice, and they have them in beadlock style also. Check the links in your shattered a wheer thread again. You should find something there.
CHeck out the link above for info on Axial beadlock rims, plus taping and balancing advice. This is your best bet if you want some really tough wheels to put your Moabs on.