I'm 6 foot and fit in ok, I could do with another inch or two for heel and toe movements though. I nearly came off at Silverstone after a foot slip under the pedal!
I'm hoping a bucket seat will help that out, and I may redrill the runners. I've seen a few tall people but no one over about 6'1 or 2 I reckon. You'd hit your head on the roof for starters!
BKVJ on here wants one, but he'd have to sit in the boot!