Unless you plan on doing some severe wheeling, just build up the d20. You'll save money initially and have something that you could sell at a later date if your wheeling needs changed.
I've built 2 cj's with d20's and had very good luck. I used moser 1 piece axles, detroit locker, and trussed the housing.
On a side note, I've got a d60 and a 14 bolt with 5.13's, detroit's, and disk brakes that I would sell.