With the brushless & lipo combos we have access to now - it just lends itself to replicating the monster horsepower days of the Group B Rallycross era.
I raced several replicas back in the day - Gollops 6R4 ( I have a pic of my Optima shelled car sat on his roof at Lydden), Welch's Xtrac Astra, and Arne Rasmushaugen's 6R4 as well. Never got round to doing a Mark Rennison DSRM RS200.....
I guess modified TC chassis would be the best option (at last they do have a use!) as they are more "scale" than the buggies.
Just need a bodyshell supplier (Kamtec perhaps?) and some suitable tracks - not too rough and "jumpy" but mixed surface.
Would love to see it make a resurgence - even with the current crop of "jellymould" aerodynamic bodyshells......