I have purchased a small camera that can be mounted anywhere like a helmet roll bar etc. I have tested on my sons kart and it seems to do realy well.  See sample at
http://www.youtube.com/watch?v=MbexxedHEKE

I am thinkong about buying more and renting them out.

They would record your whole night and I would include a DVD of the footage.

Please let me know if you might be interested and what you think a fair price would be.

Thanks Mike