This may take several posts as there are different aspects to the question, but the short answer is surely no. Valid questions can be raised about his judgment, his due diligence, and perhaps his strategic thinking. But there's no evidence beyond some over-the-edge slurs (in my view) in some newsletters published over five years or so (out of 30 during which Dr. Paul published newsletters). I've done some blogging on this over at the Register's "Horserace '08" blog, and I have more I want to say, probably tomorrow.
To refresh, if you haven't been following. Jamie Kirchick at the New Republic posted a piece Jan. 8 quoting old Ron Paul newsletters that had some veering-on-racist comments and at least insenstive anti-gay stuff as well. I was too busy to read the piece until yesterday. I have little doubt the quotes are genuine, though some could use more context. The question is who wrote them and how much supervision Ron exercised over material that was going out over his name and was a source of revenue at a time when he was practicing medicine, trying to make sure his five kids had a good start in life, and in the last couple of years considering a political comeback. Reason has done a good piece and Jacob Sullum has written a good column.
The short version is that after Dr. Paul's poor showing as the LP candidate in 1988, Lew Rockwell and Murray Rothbard started developing an approach to advancing liberty they dubbed "paleolibertarianism," combining anti-statism and conservative cultural values (family, religion, respect for tradition, impatience with weirdos, hippies, disturbers of the peace). It was conceived as an outreach to the restless right. It got tied to Pat Buchanan for a while, the divorce coming as Pat moved increasingly toward "economic nationalism." It's likely though not nailed down that Lew wrote much of the stuff in question, in an effort to talk the language of the target audience. It wasn't the craziest thing libertarians have done to try to reach out to other groups with which they share some values or affinities, but it didn't pan out that well.
Several people have noted that in 35 years of public life nobody has reported hearing even faintly racist remarks drop from Ron Paul's lips. My contact with Ron Paul has been sporadic over the years, but it began when he was first elected to Congress, I was living in DC, and was assigned by Conservative Digest magazine (long defunct) to do a profile of him. He strikes me as an individualist to the core, who sincerely believes, as he told Wolf Blitzer that it's impossible to be a libertarian racist, because he judges people as individuals and understands that a free society will function best when most people do so as well. As Ayn Rand put it (paraphrasing), racism is the lowest form of collectivism. And I've never heard anything faintly racist come from his mouth.
Anyway, I don't think Dr. Paul or the campaign have dealt adequately with this issue yet. It was a hit piece that tells us something ugly about how Marty Peretz views libertarians, but there was enough "there" there to warrant enough details to put the issue to rest.