Amy Acker says Spin-offs aren't likely to happen...
Take a look at this article...it talks about the spin-offs and some news about what would have possibly happened to Gunn http://www.syfyportal.com/news.php?id=2584

eeek i dont like that Gunn idea at all, we know how poorly things turn out when core characters turn evil lol (expect in the case of buffy s2)

Yeah, I didn't really like that idea either...