While there are a couple companies that make an adapter to put MRAP wheel on the 8x6.5 bolt pattern, the issue comes in that these are basically a semi truck beadlock rim.
I can't tell you for certain, but I don't think anyone makes a low enough profile tire to put on these rims and still make it fit under a HMMWV. HMMWV is stock with 37" tires, the MRAP is 46". The largest tire that fits comfortably on the HMMWV is 40", though with body lift and suspension lift I believe you can go as high as 42" before rubbing during sharp turns becomes a serious issue.
So semi tires likely won't work with the HMMWV, and standard light truck tires likely have too small/thin of beads to lock properly with them, defeating the purpose of even having a beadlock rim.
I may be mistaken with the above info, but I spent a little while searching and can't find any proof anyone has used them with a HMMWV, though they do seem popular with some of the "lets massively jack my truck up until I can't climb into it without a ladder" crowd.