I've also gone down a tfb route:
Regenerate - Event, $7 cost.
Do this any number of times: trash a card from your hand. Gain a differently named card costing up to $2 more than it.
Differently named because Villa and Cavalry. If both cards are in the game, then... well it's a 3 card combo, so I'd let it pass.
Assess how much you want to play during the turn, and you much you want to remodel.
First to play this on Fortress wins the game by piling Duchess+Estate+Copper.
I presume silverspawn meant Duch
y, but either way their point still stands. Firing this with a single Fortress in hand allows a player to pile the Duchies and Estates--likely netting 32VP/48VP--as well as any Alt-VP card (except the last 4 Castles), and then pile at least one Kingdom card pile (only $7 or $8 cards are out of reach, and there are not enough of those to fill a kingdom).
A solution would be for the player to set aside as many cards as they want, then to remodel those cards. This loses some synergies with certain on-trash abilities (e.g. Rats, Cultists), but I think the Fortress issue is worth that cost.
There's probably some crazy combo with Sceptre, but you said to go big.
Quick question: who chooses whether the other players receive the next hex or discard a copy of the card gained? The wording is ambiguous currently.
It should be the opponent - thanks for pointing out the ambiguity. I will add “their choice” similar to how Torturer is worded.
If you do this, you should technically add "(or reveals they can't)" after "discards a copy of it" to deal with accountability issues (see Villain).
When I first saw the card I presumed they had to discard the copy to avoid the Hex (akin to Mountebank). In that case the language should be: "Each other player may discard a copy of it. If they don’t, they receive the next Hex."