Doomed Bank of America CEO Ken Lewis' last day is December 31—and the "too big too fail" bank is at such a loss to fill his position, they may name a stopgap chief for the interim between Lewis and his permanent replacement. Bloomberg reports that "at least four external candidates," including Citigroup director Michael O'Neill, have turned down offers. BofA's search is complicated by the fact that their choices must be vetted by government regulators. House Oversight Committee Chair Edolphus Towns' gave internal BofA candidate Brian Moynihan the kibosh last week for insufficient leadership experience, and Treasury Department paymaster Kenneth Feinberg is reportedly keeping a close eye on the hiring process, too. What's more, warring shareholder factions—including the group that led the anti-Lewis revolt—aren't agreeing on favored candidates, other than ones that have already turned the position down.