What about KC Coppersmith ->$31 valued copper:
BM->Play all coppers, HoP->Mandarin
Chancellor, Counting House
x10 (perhaps this makes it a little hard to not end on piles, so maybe only x9?)
Play all Coppers in normal buy phase
60 coppers *11 *31=$20460
edit: 60 coppers, sorry.
Yeah, Black Market+Mandarin trick seems good here. Other treasures (like Bank!) can also be played with the Black Market for huge cash, then you can redraw them all with a Crossroads (assuming you have tons of green in your hand). Although now that I think of it, it's challenging to find enough green for Crossroads to draw back all 40 Silvers and 30 Golds.
(In fact, if you're playing Bank at all, then Pirate Ships shouldn't be worth it. Each treasure trashed by a Pirate Ship only adds $30 in the eventual KC'd megaturn, whereas it adds $10 to the value of your Banks _each time you play treasures_, so in other words, $110 total over the 11 plays.)