I can't say I have a single "dream pipe" that would eclipse all my others, but there are a few high end items on my bucket list...
1) A Dunhill DR-graded Root Billiard. It's the classic shape, from the classic English pipemaker. The DR */A's are sometimes still a little weak in the grain department, so I'd probably shoot for ** or *** (B/C). Any higher than that and I'd never dare to smoke the thing.
2) A Talbert Briar. Definitely not a Halloween pipe, because they're way too big and crazy for me. And not all of the regular Talbert Briars speak to me either. But Trevor has a great sense of style that I admire. Someday, just the right pipe will come up when I happen to have some money to burn, and I'll actually manage to catch it before someone else snags it.
3) A pre-trans Barling, just to see what all the fuss is about.
I don't make a big point of looking for any of these, and don't feel any great loss for not owning them yet. At some point, the time will be right.