I keep the camera (Nikon D200+18-50mm lens) in this bag inside of this tank bag.
Tank bag is huge (as is that camera bag) and there is still enough room for other stuff, witch is important to me.
When I find some appropriate foam, I'll put it on the bottom of the tank bag (as in the second link Invader posted) to dissipate some of the vibrations.
I've read quite a few reports on AdvRider about cameras in tank bags succumbing to vibrations and much many more that survived without issues.
What usually happens is that (plastic?) ring that conects lens to the camera brakes.
I would recommend using the smallest and lightest lens (or more then one) that does the job for you.