Upside down rig

[dodger]

I've been doing an upside down juggling finale for a while now. As it stands, I have two strong volunteers hold on to a skateboard, and I hang off of that. It's portable and makes me feel clever, but I think I want to move to something higher, mroe impressive, and more reliable. I've heard that there are rigs for doing upside down straitjacket escapes that would work. Something like a tripod with a rope hanging down. Does anyone know how to make/buy one of these? Ideally, it would be something that would collapse small enough to be reasonably portable -- ie no wheeling it around -- but that might be too much to ask for.

Thanks,

-Dave