For those who do not like to be professional, I found something that would not go against your principles Nat Filmore could even have one stuck to his helmet or when mowing the lawn can fit it to the mower!
They are cheap as chips.. and seem to have a decent resolution 720x 480 and can easily be mounted with double sided foam tape almost anywhere.
I'd buy several if the postage wasn't silly! I don't want to buy from Hong Kong!
I very much doubt these are resiliant enough for use on a single seater. And/or in the wet. Sound quality (if they have mics) will be rubbish as well.
But, for 99p you can't go wrong if you're happy to fall for the postage costs.
Tristan Cliffe - MSV F3 Cup - Dallara F307
Monoposto Champion 2008, 2010 & 2011 with a Reynard 883 and a Dallara F398, and F3 Cup and Team Champion 2012
From our, admittedly limited, experience with the cheap stuff, was that anything with a hard drive is rubbish, and anything with a battery pack will need reinforcing or packing. Either the battery will vibrate away from the contacts (pack out any remaining space with tape, or the battery retaining clips will break (bodge it)
However, for a couple of quid, even if it only lasts a couple of races, could be worth using.
I once used a HDD camcorder and that was rubbish. I didnt use it again... I did try my mobile phone at Donington, recording would have been good, if I designed a better mount with anti vibration... most of the picture was too wavey.
The mount for my Smartycam works just fine, how ever it s bit on the bulky side.. picture is very good and no issues... I dont think people are willing to spend 700 for a camera setup so this is a cheapo alternative.
These little things run off an SD card so its solid state, and you can mount it with foam/tank tape to absorb vibrations.. They are only a few quid so not a big deal if it breaks or shakes it self to peices.
Nat Filmore could even have one stuck to his helmet or when mowing the lawn can fit it to the mower! 
