I think that ticket would have a fine balancing act to make. If Giulaini only spoke out on the issues where he's mainstream, and Huckabee only took his issues, it could somehow, contrary to any sense I have of these guys, stitch the party together.
It'd take a lot of work though, and it would take the sense for all sides that "their" guy on the ticket would have his way on the issues where he's "right."
We know Giuliani is strong-willed enough to get his way on taxes and the war. Is Huckabee the kind of guy who could stare down Giuliani on guns or abortion?
Update: I nearly forgot! The people who are left out in the cold by this ticket are the anti-illegal immigration people. Giuliani is of course well-known in those circles for his preservation of New York City's "sanctuary city" policy, and Huckabee will become known as the guy who coddled Tyson as that company hired illegal aliens left and right.