I don't think there are any absolute answers here, though it does seem
worth the time to consider various scenarios and what the likely
outcomes would be in both gear up and gear down configurations...

Let me add this tidbit for the gear up on pavement scenario.  I have experienced a nice gear-up landing on a runway (I know, that's not off airport) but it is just like a paved surface - actually it was a paved surface.  The advantage to this is the very short stopping distance with out high deceleration Gs.  The disadvantage was the drift to the right because the giant chromed pitot way out on my left wing got a bit worn down acting as a skid and the exhaust pipes on the left side of the cowl are more slippery than the composite cowl and belly scraping along the ground.  The inboard flap trailing edges were worn evenly thus the wings were not damaged since neither tip touched.

 

Note that a gear up landing on pavement is a good short field technique, but there is no directional control.  The runway was 75 feet wide, I landed on the centerline (Commercial pilot training) and ended up with my left wingtip just off the runway.  I am looking for a picture of this that shows me 30 feet or so short of taking out a taxiway identifier light box.