CheapXJ,
My silly SWB roommate with a TJ went full width but used hummer rims. They have like 7 inches of backspacing or something. It will bring the wheels in more, that way in case you wanna narrow them down(axles) in the future you still have that ability too. plus you keep the nice short axle width. I still believe you gain some wheelbase by going fullwidth and hummer rims over stock axles. You will be a little wider than stock WMS according to him. You can keep the tires under ur rig and not need huge fenders?
I didn' tknow if you've looked into it.