[crASH]

I have been exploring a 289 build myself and you took the words out of my mouth. I would have suggested looking into Mr Bruce's bodies in addition to Unique and ERA. There might be some other more obscure sources but I think those three will likely be your most reliable sources for a slabside body. Superformance has started building a slabside roller but I don't know if you can buy just the body. Doesn't hurt to ask. Good luck in your search.