Okay, so I know four-card combos are not really worth studying in depth - especially when each of the four components is unique and irreplaceable for its function, but this one is still pretty fun.
Every turn you play Golem, which then plays Scheme and Chancellor (
in that order!). You buy a Province, reshuffle your deck with three Stashes on top, and then replace your Golem with Scheme. Rinse and repeat. Once you get the combo set up, its a guaranteed* Province every turn. In a solitaire game I got 4 Provinces in 11 turns, and all 8 Provinces in 16** turns.
*Any discard attack will of course mess this up completely.
**The extra turn came about because on one turn I accidentally played Chancellor first,
then Scheme, which made my stashes miss the reshuffle. But even with this mistake all it took was a single play of Golem to get the deck back in order.
The neat thing about this combo is that it avoids*** the one downfall of Scheme/Golem combos. Normally it's a problem if you draw your Golem with your action cards in hand, since then you can't play both actions and return Golem to your deck. But if you have Golem in hand plus three Stashes, then there is only room in your hand for one other card. If that card is Chancellor, then you play Golem, which then plays Scheme, giving you the action to play Chancellor. If the card is Scheme, then you play Scheme first, then Golem, which plays Chancellor.
***The only way the combo breaks down is if you have Golem, Scheme, Stash x3 in hand, and Chancellor is on top of your deck. You could avoid this very unlikely problem by buying a fourth Stash.
Here's the solitaire game where I tried this out:
http://dominion.isotropic.org/gamelog/201203/06/game-20120306-105649-e13b89b9.html