We had a gear up here recently and the way we dealt with it was to use a giant tow truck with a crane like this.
Straps attached to the engine mounts (removed the cowl of course) and then under the fuselage just behind the wings with lots of padding. Lifted it enough to get the gear down, then rolled it to the hangar. Almost no damage to the airframe, although it will need a new prop and engine teardown/rebuild.
I would guess that this kind of crane would be the best way to do it for a flipped RV, just flip it back the way it came over - not going to do much more damage than has already been done.
Procedure we have used successfully is 1 person on each wingtip, 2 people lifting the tail, 2 more people in front of the plane waiting to catch tail as it comes over.
In soft sand and/or snow, we have accomplished this without even damaging the fiberglass spinner.
Do ya'll draw straws to see who gets that job? I have visions of a giant flyswatter.
About 15 years ago I watched some poor soul flip one at Reklaw, landing long and standing on the brakes over the lip into the dip. Twenty or thirty guys ran out and flipped it back on its wheels before the dust settled.
-