I bought a fiddle/mandolin version from Dick Greenhaus (Camsco's got 'em) at a recent festival. It's even got a little notch for the bow!   The only near fatal disaster my fiddle ever had was being sat upon by a flute player. The flimsy-looking wood of the fiddle and bridge were fine. My metal shoulder rest was bent.

We have nails in the walls at the place where our session is. I use Rick Fielding's trick of cutting slots in a small leather strap and putting it over the two end tuning pegs. Other folks wrap coat hangers around instrument necks. It's a lot more work, more potential instrument damage, and it takes much longer than 5 seconds to remove them.

Back to the pub prop - I think they're made mushable to prevent damage in the first place. They absorb a bit of the shock of a hit. Imagine what could happen if someone bumped your instrument hard enough in a completely rigid clamp. It's not good when the part holding the instrument is so easy to accidentally open, though. Maybe the same rubbery material and a stronger neck-holding clamp would be the thing. I haven't seen any other types of clamp thingies for sale, but they're probably out there, or could be made relatively easily.