If you want to go Mardave how about these:
http://www.youtube.com/watch?v=sVYD0rNOeFc
However, if we did go down say the route of 1:12 scale, there is nothing stopping us as a club devising a rule that states exactly what you are allowed to run for tyres, speedo, motor and cells. Only the car and radio is optional if you really want to keep prices down.
I think you have a valid point on grip levels - that will be key in what ever choice was to be made...