...what about finding a clean 5.7 or 6.4 8-lug Hemi Power Wagon or 3/4-ton 4-door or similar Ram and doing your own upgrades with gears, lockers, tires, lift, etc.? You'd already have big axles, lift kits off-the-shelf, etc. Could even drop a Dakota body on the PW frame and have a full-width Dakota (lotlotlot of work tho). My Dak has full-width tons under it (89 Ford D60 and a 02 GM 14b).
Might even be better off starting with a regular 4x4 Ram (non-Power Wagon) so you can put in whatever traction aids and winch, etc. you'd want, and you can avoid the initial "Power Wagon" mark up.
If I were wanting to 'have' a truck for overlanding and moderate rock-crawling I'd absolutely start with a 3/4-ton Hemi Ram 4-door and just build it 'big', 40's minimum. Lots of interior room, lots of capability, maybe the only drawback is it being a 'full-size', but my truck is living proof that full-sizes can go just about anywhere, albeit pin stripes and body damage are a bit more 'likely' but often avoidable with careful driving, and armor 😉.
Honestly, based on what you're intended use(s) above, I'd say Ram 2500 Hemi upgraded to 40's and you are 'there'. If full-width axles on a Jeep will fit the trails you want to do then having a full-width body over top of them will fit too 👍. My giant PW is 8 feet at the tires - I've had it all over Moab, and a lot of places in Colorado that folks said it wouldn't fit, and what I discovered after doing the trails is that most folks don't really know how big their stuff really is.
- Sam