Another not impossible situation is that there are a dozen or so Republican US Senators who are absolute enemies to conservatives. After the election, with lame ducks and people those who will do anything to punish Constitutional Conservatives, would those 'pubs out of spite vote for the Obama choice?
They might well vote for a stealth liberal or, as someone suggested, a sitting RiNO senator (GOP Senate caucus -1) or primaried RiNO (like Eric Cantor). The "good government" </off Bush 41 sloganeering> Republicans would lunge at such a nomination, and the result would be another rollable, "grow"-able Anthony Kennedy/David Souter on the Supreme Court.
An AJ like that would be every bit as much a threat to, e.g., RKBA and prolife cases as another Diesel Kagan. As Pew Associates pointed out in their 1999 political sociology survey, when gun-control was a hot issue after Columbine, it's the "good government" and business-management Republicans who are the weakest on gun ownership (they don't want their employees owning them) and might, Pew helpfully suggested, provide the allies the Left needs to eviscerate 2A.
Under my scenario, I don’t think a recess is needed - just a Dem majority on Jan 4, and O in the WH until Jan 19.
As for a recess appointment - that would be difficult with a GOP majority. The “recess” must be longer than 3 days. Someone can be there and conduct some meaningless “business”.
Will some Reps defect? Maybe - perhaps O will pick someone of universal acclaim who is a centrist that all will agree upon, then fight this fight with the Ginsberg vacancy. This would be best for the institution - but it won’t happen. Otherwise, not enough will defect to give O the appointment he wants now.