1). Susan Collins' spokesman says she'd vote for Don't Ask, Don't Tell repeal, under certain procedural circumstances, before the Bush tax cuts are extended.
2). A spokesman for Lisa Murkowski says, "of course, [Defense Authorization, which includes DADT repeal] is a priority but she believes, like her colleagues, that first she wants to see the Senate take care of the budget and of these looming tax increases."
3). Richard Lugar's spokesman says that tax cuts, government funding, and the START treaty are his top priorities, but would vote to debate the Defense Authorization bill under debate terms that were fair to both Republicans and Democrats.
I'm skeptical. Murkowski's and Lugar's positions in particular seem completely compatible with McConnell's pledge: tax cuts and government funding have to be the priority. Obviously McConnell would like nothing more than to win the day on tax cuts and government funding, and go home for Christmas. But, notably, that's not where his caucus is united. His 42 members pledged to keep stuff off the floor until after those impasses are bridged. If and when that happens, he'll start losing people.
It's possible he'll start losing people before then. That's what happened during the Wall Street reform fight -- but only after Harry Reid forced the issue and made Republicans, repeatedly, vote to block debate. After a few days, they had enough.
It could happen again. If these three Republicans broke ranks, that would be enough. But as of now, there are no plans for him to repeat that strategy Don't Ask, Don't Tell.