Following on from a thread on "Racechat", how about running a "SuperMoto" style event? Buggy's on a TC circuit - mass starts, slick/worn buggy tyres, minimum ride height of say 20mm, no TC tyres or "treaded" tyres.
Cars would undoubtedly be stupid fast, but would also be going sideways a hell of a lot........
As for the computer coping - the Banger club I linked to above seems to have no problems. It gets easier the more people that run PT's, but I've raced in 30 car races and that's in a confined oval!!