Another idea, Cornucopia Rebuild:
Rebuild
+1 Action
Name a card. Reveal cards from your deck until you reveal a Victory card that is not the named card. Trash it and gain a Victory card costing at most 1$ per differently named card revealed more than the trashed card. Discard the other cards.
Edit: Maybe instead of "up to" it should be "less", but that's a detail. I think you get that this tries to reduce the one-card-strategy aspect of Rebuild.
took me a minute to get it, but this seems worth testing. Prior to having duchies, you'd have to get very lucky to go estate-> duchy if your deck is just copper, silver, rebuild, estate (drawing all three prior to estate). Once you've got duchies, it's a bit better, but still weak. So you'd have to buy stuff besides rebuild, silver, duchy, in order to make the deck work. And that's the thing that rebuild needs.
The trashed VP card also counts as one of the revealed cards, as I understand the card text; so it works as a normal Rebuild just by revealing Copper and Silver before the VP card. In Shelters games or with Looters, it becomes even easier to use Rebuild as usual.
Therefore I think this is far too strong (probably stronger than the printed card); it gives a very good chance to go e.g. Gardens->Province, and a realistic chance to directly rebuild Estates into Provinces if you have 4+ different non-VP cards in your deck (you just need to buy 2-3 different support cards for Rebuild even if there's no Shelters/Looters; you'd sometimes do this with the original Rebuild anyway).
The idea is interesting, but the card should at least say "less than" to weaken it; probably it needs even more nerfing.
(I still think my in-hand idea is viable as well. I guess since nobody commented on it y'all disagree. I'm petulant about it, tho.)
I agree; but I think it would need to cost $5 to become reasonably weak. Actually I considered just this variant as a fan card before Dark Ages was released; back then I thought it might still be too strong at $5.
I wonder why Donald didn't consider this version; it'd be easier and more interesting than the printed card...