hrrm, IIRC Nintendo used to say similar things about Rare too. (It'll be done when it's doen etc...)
Microsoft is probably one of the few companies that has the money and is willing to support Rare. Anyone else would have dumped it by now and would have farmed the intellectual rights out.
I don't see 2 rare titles being released at the same time as launch titles. They only ever concentrate on releasing one game, i dont think they're developing 2 games right now so they can be released as launch titles for the 360.