The Bantam has been on my wishlist. We've got an old Willy's CJ too. There's a bunch of plans on the internet, I may try to take some of the basic dimensions, but change the axles to 5 on 4.5 and lighten the load up a bit. I'm still in planning stages though, but I think honestly I want 2 trailers, one that's a bit bigger like a tear drop with AC, because the GF isn't thrilled with no AC. I can get away with it some with the doors or top off of the Jeep, but not sure that would fly May-October around here for her.
I've got some varying ideas on what I want though for the trailer, I was also thinking about making it a size that I could throw on a small topper and sleep in there too, but I see a lot of people really like the RTTs. Basically I'm in idea overload, but that's part of the fun too.