Michael,
I hope you don't advocate the chassis number scam!!!!
You make some good points but you maybe miss the object of the thing. You can run in classes (as in rallying) and can still be an outright champion without winning a race. You need to keep scoring class points. Anyway, the whole point is that this series brings cars together which race in other championship but get very little chance to race competitively together.
Its a challenge but I wouldn't mind betting that you could build a good useable (reasonably competitve) small capacity car for a lot less than your figures.
I know of a race prepared A35 which was sold as a going concern (complete with roll cage which is mandatory) for around £3000.00. It is racing with the CSCC on a regular basis.
