someone did that with a van for bmx biking. They got HUGE air and then died in the hospital. I'll try to find the vid on youtube..
Not the best vid, but you can see the jump. It looks pretty painful, no blood or screaming in pain or anything.
http://www.youtube.com/watch?v=cJV-j...eature=related
You could also get something like a 1/5 nikko car and stick a ramp on that.