I've owned three one-man riggers, each one better than the previous one. My current (and probably last one) is one of Steve Koerner's (now manufactured by MM). It is very similar to the Udo version, but uses a gas shock for support rather than a screw and crank. I was always bashing my knuckles with the crank and find the gas shock to be easier and quicker. It's the only US-manufactured one worth looking it, IMHO.

Mike