I used to spanner for Doc Enderby from the 850 8 Port Mini right through to the Karmann Ghia, which he still has.
I think Andrew is right, it would be a tough battle to get a full grid of cars out there, clubs would be very hard to convince to run such a championship.
There are places they can run such as the Combe GT series but look at the grids for that now, just 9 cars the other week.
The other thing is that most of the drivers of the period are that much older, though has to be said, a few are still racing, and so are their sons in some cases !
I'd love to take the Karmann Ghia out though, having spent a good part of my yoof building it !