No interest in a Goldberg return, and the rumors of him fighting Undertaker in 2011 (I think that's what it was) was just that. He said in 2010 he had no intention of wrestling again, and I think he even said he could care less about the Hall Of Fame.
A match with Ryback is the only suitable match I could see him having, but I'd much rather see Ryback and Brock go at it.