First, I already posted Romney's press secretary calling Palin inexperienced during the campaign.
Second, Romney has the most to gain if Palin can be destroyed before 2012.
Third, there are plenty of rumors out there that these attacks are indeed coming from former Romney campaign workers who were absorbed into the McCain campaign after Romney suspended his run.
Lastly, you have offered nothing in return while I have painted a fairly decent circumstantial case.
Here are some links to stories that absolutely link Romney people to the anti-Palin stories:
Romney People in McCain Campaign
Romney Won't Say Palin is Qualified
Just do a search "Romney on Palin"
Soak your head.