IMO this is a litmus test for the Tea Party. They have the muscle to shut down the government if they all refuse to vote for the debt ceiling increase, which means they have the muscle to force pretty much any cuts through that they want. For all intents and purposes they can dictate terms on a "take it or leave it" basis.
Does anybody really think they will do it?
IMO the most likely scenario is a quick up or down vote...at night if possible...then a bunch of excuses as to why it had to be done and why they could not force spending cuts through with it.
If ye love wealth greater than liberty, the tranquility of servitude greater than the animating contest for freedom, go home from us in peace. We seek not your counsel, nor your arms. Crouch down and lick the hand that feeds you; May your chains set lightly upon you, and may posterity forget that ye were our countrymen. —Samuel Adams