There's a general bipartisan agreement on a long-term deficit reduction plan?
Yes. Both sides agree on spending cuts. Negotiation of differences is not really a major problem. They keep painting it as an ideological difference, but it's really just dickering over numbers. That's nothing new or insurmountable.
What is it, and does it include any tax increases?
As I said, that's the sticking point. It still seems that the GOP will agree to no long term plan unless there is a promise never ever ever forever to raise taxes.
If it doesn't include any tax increases, a significant number of Democrats still agreed to it?
See the most recent budget compromise. It was not tweaks and amendments to the budget Obama proposed. Instead, it was a compromise starting from the GOP proffered budget*, and it followed the granting of an extension of the Bush tax cuts (even for the wealthy) in exchange for an extension of unemployment benefits. So, to date, the Democrats have indeed already agreed to spending cuts without a tax increase. In fact, since Obama has been in office, various taxes have only been cut.
Who would they be appeasing by claiming that they voted against raising the debt ceiling?
Bachmann's base, for example. She has pledged never to vote for an increase in the debt ceiling. Yet she must know that we really have to increase it. The McConnell plan would essentially be a way to raise the debt ceiling yet still let her claim she kept her word to oppose it.
*[ETA: And by "compromise" I mean the Democrats gave the Republicans everything they first demanded, but the GOP refused to take "yes" for an answer and demanded more--even threatening the shutdown of the government over attempts to push ideological amendments regarding Planned Parenthood and NPR under the guise of deficit reduction.]
The Tea Partiers will be more than miffed that the Republicans gave up the one thing they wanted in exchange for raising the debt ceiling -- a chance of attaching massive spending cuts to the debt limit increase.
I'm sure that's what they'd like to hold out for, but I'm equally sure they know they'd be blamed if the U.S. did default on its debt.
Plus it would be a win for the President, who would get what he wanted to begin with, and we can't have that.
Not really. Obama has been saying he wants a long term plan too. That would be his preferred resolution to this crisis. However, if it doesn't happen, he would accept a short term plan that raises the debt ceiling and continue trying to hash out a long term solution.
Obama would not like there to be no long term resolution in place for another year. The McConnell back-up plan could keep the "crisis" going right up to November of 2012.