Okay, so this isn't a formal endorsement, but Rush Limbaugh's homepage is absolutely Pro-Romney and Anti-Huckabee. Rush correctly sees Huck as the wedge that will divide and eventually destroy the Republican party, not to mention that he would be annihilated in the general election. Rush also correctly sees Mitt Romney as a full-spectrum conservative with the intelligence, charisma, and competence to win the general election, unite all 3 elements of the Republican Party, and bring real change to Washington.
Here are some images from Rush's website, prominently featured on the homepage: http://www.rushlimbaugh.com/
HUCK WOULD DOOM THE REPUBLICAN PARTY