Absolutely the LR3/4/RRS can have the body lifted off the frame, and I too have wondered about doing a small body lift for more tire clearance. I think one of the obstacles would be the bumpers that mount to the frame which would require some sort of filler be fab'ed to cover the gap. It would take some doing to come up with something that didn't look completely ghetto.
I believe there's enough slack in the wiring harness for a 1" lift but have not verified this.
Possible other sticking points could be the steering, fuel filler, and any rocker protection/sliders you're running. Then again, I've never done a body lift on any vehicle much less an LR3 so I don't know what may or may not be involved.