Maybe you could try sandwiching some Aerogel insulation between two sheets of stainless or aluminum to form a super heat shield. You can buy the stuff on eBay:
http://cgi.ebay.com/Aerogel-Mat-Aspe...item19bc28be26
http://www.aerogel.com/Aspen_Aerogels_Pyrogel_XT.pdf
I believe the Kirkhams used this on their $1MM Billet car on the trans tunnel