inazuma,
G Force in WA make an aluminium body combination. Lots of $$$$ I would imagine but an excellent Kit.
Check out
www.gforcesportscars.com.au there is an aluminium body car picture in the "for sale" section at $85k. I do believe they make the aluminium body on request for their kits. (Their latest catalogue lists it as an option.)
Good luck!!!!
TC