This shoulder mount might be useful to those who use DSLRs for movie making. It's called the HabbyCam (don't ask me why) and it's reasonably priced at $250.
It's essentially a brace, is made of aluminum and stainless steel, and weighs only 3 lbs. The shoulder bracket is drilled with holes that can accommodate other accessories such as sound recorders and the like.
I don't have it so can't recommend it, but it certainly looks as if it could work well. I'm guess some enterprising person will eventually cobble one from hardware found cheaply at Home Depot etc.