What about the more drag orientated guys ?
Hauser, Webster, Sleath, Andy Robinson ?
or Simpson Motorsport who built Norris' Evo ?
They can all throw a few tubes together. Or further afield, Andrew Gallacher ?
Or there's bound to be a lot of rally/cage guys who could do it too.
Or perhaps ask over on Turbosport, custom fab might be a bit more common over there with the MK2's etc.