I seldom even get a chance to listen (and usually have less interest in hearing for 3 hours the "chewing and milking" of something that is less than I can usually find on FR, Drudge and my email in a few minutes) but whenever I did, it seems that he's been trying to keep his options open, while still trying to subtly play the kingmaker.
Also, many open primaries threw the monkey wrench into the race early, and Dems are openly using his ill-considered "Operation Chaos" against hapless Republicans (who allow it - something Tea Party could easily unite in stopping after the elections) so he doesn't want to go out on a limb with predictions and be shown wrong, especially since he can hide it behind the claim of "not interfering in primaries" - it's a win-win for him - much easier to just read and comment on the polls that he can pick and chose and interpret any way he sees fit.
I don't think he is too pleased, because he knows that he will have to "carry water" for Mitt if he becomes the nominee (which Rush said he will no longer do for GOP after McCain's campaign), but he seems to really favor Santorum, while sliding over and ignoring his big government, statist résumé.
He's been harshest on Newt, even before Paul Ryan's fiasco of sticking the massive, unvetted Medicare reform into otherwise decent, as first step, and winnable budget plan.
The few times he had Newt on his program, he kept cutting him off, and generally wasn't very interested in explanations as much as trying to show off himself and his own "brilliance" and importance / influence.
Many times when he spoke of Newt, it was only to bring up something that he couldn't bring himself to admit he was wrong; mostly phony issues, that he locked himself into to disagree with (harping on "Ryan plan" or replaying "Era of Reagan is over" etc.) but not giving Newt credit for the things or ideas he brought up.
People laughed at Reagan's "supply-side economics" (Bush called it "voodoo economics") the same way they are laughing at some of Gingrich's ideas, even those which seem tame by comparison. There is no question that Rush feels he would see his influence or position of conservative "thought leader" greatly diminished if Newt becomes President or even just a nominee.
"If you have no enemies, you are not important enough to have made any" - Alexandre Dumas
"Our worst enemies here are not the ignorant and simple... our worst enemies are the intelligent and corrupt" - Henry Graham Greene
As Rush would say......"You may have inadvertently stumbled on the truth."
Though I would say that you've zeroed in on the truth.