I bought a Yamaha RBX350 bass and a Yamaha SBG1000 six-string online through eBay. Both transactions went smoothly, and the instruments were exactly as described. Mind you, if that hadn't been the case, I would have had some trouble sorting it out.

BTW, the Yamaha SG and SBG series guitars are all like double-cutaway Les Pauls (only better, IMO). Click Here
The seller is wrong about the SBG series. Yamaha changed the name because Gibson was threatening leagal action over the SG designation.