What's the most backspacing you've seen?

[Marlin]

I would try talking to marlin or littlebeast. Iirc they bothe have larger width rims with close to a factory offset, so that should at least be a little more backspacing than factory.

Yep, you got it. I got as close to factory offset as I could.
Here is where I started, and since then, I have kept the same wheels as shown here, but went up to a 34"x11.5" tire. I also lowered the front end down to almost stock height, looks funny, but improved the offroad handling drastically. My VX just sits in the driveway most of the time, less than a tank a gas through it a month.

Ultra Goliath wheels: 108mm bore
6 on 5.5, 18x9, 5.5" back space, +12mm offset
General Grabber AT2 275/65/18 P-metric
OME919 springs
14 turns on t-bar