I never owned a Pitbull 45, but I let one slip through my fingers once and I'm STILL bummed. It's a great amp, with some of my favorite cleans ever (and my favorite from a VHT/Fryette).
If there's something I regret selling, it's my Mesa Single Rec stack. I retubed it, and it just wasn't the same. Instead of considering my options I just sold it like a moron, and tried a bunch of heads that I didn't like as much and didn't hold on to. The cab went with the head, and it while it was old the tolex was still great and the speakers were perfectly broken in.
Come to think of it, I think a thread talking about amps that you sold and DON'T miss would be pretty cool...