What are the results for likely Republican voters?
The latest national Republican likely voters poll I found is from Rasmussen, conducted on 1/17/12. It shows:
http://www.rasmussenreports.com/public_content/politics/elections/election_2012/election_2012_presidential_election/election_2012_republican_presidential_primary
Romney 30 Gingrich 27 Santorum 15 Paul 13