AMT produced a limited number of 1:25 dealer promos (friction powered). VERY tough to find, but they do exist.
I know there have been resin bodies offered by various sources over the years, but all I can currently find is an AWB body by Fremont Specialties- it would take some work to un-alter the wheelbase, but I would imagine it's do-able (maybe with the help of a Barracuda donor body?). 66 Valiant AWB 1/25 Resin Body & Hairy Canary Decal from Fremont Racing | eBay