Sorry if I'm repeating an already answered question, but I really did try to find out the answer on my own (to no avail).
One of the adultswim bumps mentioned Seth M. speaking at a college, where he answered questions (one of which was that Stewie was based on Rex Harrison). AdultSwim pointed to the adultswim.com boards for the rest of the summary. I went there, but couldn't find anything.
Does someone here have a link?
Stu (who is a big fan of the Griffins)
NP: Me And The Wind by XTC