What's the easiest/cheapest way to do 8 lug 20" ?
There weren't any 8 lug 20s in military use. Shouldn't be too difficult to find some aftermarket ones on Craigslist though. Decent looking ones may be harder to find, however.
I don't know, but I have some aluminum MRAP wheels that are 20". The lug pattern on them is a 10-lug hub piloted style, so many people get adapters to run them on deuces. You could get an adapter made to make them 8-lug as well. The only downside is they might would have too much offset. The 4 wheels I have are brand new, would take $100 each.