I think my current bar-mounted version for the MD80 is as far as you can go without spending loads of dosh on fancy equipment. Example:
YouTube - parks MD80 barmount-desktop.m4v
It's a 'pocket' made of foam and silicone, into which the MD80 is thrust, and it works fairly well, partly due to the soft padding, partly due to the Wisper's front suspension.
Body-mounted variations all have the same problem - move your body and the picture moves too. Bar-mounted versions like my current one also have a problem, which is the opposite, of course! If your bike ain't pointing in the 'right' direction, you don't get a photo of what you might be looking at.
I'm thinking of going down the route Lemmy has put forward in a different thread, that of a body tripod (gorillapod) with a 'proper' camera mounted onto it. The result he posted using such a device was quite impressive. (Doesn't solve the problem of what you're pointing at, of course; that still requires an answer).
A.