I think you underestimate how Machiavellian Pelosi is. If she tried to take the Speakership now it would re-unite the GOP and she would fail. If she gives the release to her caucus to support Boehner then he retains the title but she holds the power.
btw, this is exactly how TX Speaker Joe Straus (super-RINO) holds power even against a majority of GOP who oppose him.
bump
With Dims and RINO's on his side, it's next to impossible to oust Straus.