hey rich...maybe try wintech video in studio city...dont have the info right now. sorry. they may only have cameras and lenses, but it's worth a try. nice guy. i rented a DVX100 from him real cheap before i bought my 100A. he let me keep it two days for the price of one.
if anything, he can probably refer you to someone that can help you out.
Speaking of good body mount scenes check out "pi" some good stuff in there. Also check out "requiem for a dream". (by the same director) There is a running scene that looks awesome!! After watching both of these movies I made one of these rigs myself using a small tripod bolted to a piece of wood screwed to a backpack. I haven't tried it with my dvx yet though.