Butterflies would suggest no. As for Rudy: this is an economic election. In the base's eyes, it's bad enough that one RINO heads the ticket, and Rudy, national security aside, is hardly a base-pleaser. Pawlenty is the only other option.
Let's not forget Tom Ridge. Ridge, having been a governor with a reasonably solid economic record, would have some chops in that regard, while doubling down on McCain's homeland security credentials, and he also has the benefit of coming from PA. He's pro-choice, which would hurt with the base, but other than that, he's probably what might be called "conservative enough."