It's the debate for the new millennia: carbon or steel for a mountain bike. But what about both? Sure, others have ventured into putting rigid carbon forks on a steel hardtail before, but you don't catch sight of the reverse too often. Since signing with Specialized to produce his latest hair metal band's new album on minidisc, Poppi acquired an S-Works Fuse 6Fattie to take on the Baja Divide route. While this was by far the lightest bike he's ever owned, Bene decided early on that the…