That's a great question. One of the underlying questions for all financials is "Has all the short money been made?" I don't think so.
Bank of America would be a good short until August. That's when they either buy or pull out of Countrywide. All evidence points to Countryslide not being purchased...
Wells Fargo has really been pushing commercial lending through its wholesale side. With commercial mortgages facing their own potential debacle, I think they would be a good short as well over the next 1 year...however an economic boon might counteract that.