K-LO has a list of Republicans whose votes on cloture she's still unsure about:

Richard Burr (N.C.)

Lamar Alexander (Tenn.)

Kit Bond (Mo.)

Gordon Smith (Ore.)

Thad Cochran (Miss.)

Norm Coleman (Min.)

Orrin Hatch (Utah)

and Bob Bennett (Utah)

More on Burr (whom I had as "Very Unlikely to Switch," but am now moving up to "Could Very Well Not Switch"):

Senate negotiators of a compromise immigration bill are writing a catchall amendment, sponsored by Sen. Lindsey Graham, R-S.C., to bolster enforcement provisions of the bill, including a more robust "touchback" requirement for illegal immigrants.

Republicans outside the negotiating team are asking that Graham's amendment, as well as a few others, get a floor vote before a cloture is attempted on the bill. "If they want the bill to have a chance, that's what has to happen," said Sen. Richard Burr, R-N.C., who said he is willing to vote for the first cloture motion to proceed to the bill to allow the amendment process to begin.

Burr left open the possibility he would vote for the second cloture motion, which would ensure a final vote on the bill, if the bill is improved from his perspective by the amendments.

So would Burr still vote for the second cloture motion--the one that would shut down debate on the bill--even if these amendments do not get a pre-cloture vote? (After cloture, they do get--at most--30 more hours of debate, but, at the end of those hours, an up-or-down vote will be taken.) He sounds on the fence to me...