Flatbotm, You into 4x4's also? Me too, I've built my share of Jeeps, Toyotas and full size trucks. My current 4x4 is a 85 GMC on 39.5 Swamper's, you can see it in the background in some of the pics. The JD2 bender came in handy on some of these builds, I mostly used it on Harley frames though.
I'm not sure of what you mean about a permanent bimini cage, can you draw a diagram and post your idea? Could be an interesting concept.
.126 wall was what I was thinking it was just off the top of my head, could be .133 anyway just a little over 1/8" wall.
Let me know if I can help in any way.- Rod