I'm really interested in seeing how this card holds up to certain things. There are a few things I'd like to see. Basically, two versions of Rebuild bots to give a baseline of how powerful it is. The first one is probably more important, and that is the non-mirror matchup bot. How does it do against wharf, mountebank, witch, young witch, and if it beats all of them, some of the combos, like YW/Tunnel, HP-terminal silver, HP-baron, etc. etc. The non-mirror would be something like rebuild (if less than say 2)>province>duchy(if late enough)>duchy or estate(if there are say 2 or fewer non-province green cards in your deck)>Rebuild>silver>duchy>estate(if it's reasonably late). Play rules could be as simple as always name province, or name estate if duchies are empty (otherwise name province), or if you want to give more exactitude, some way to be able to trash province->province to end the game sometimes (I doubt this will be very important though).
Also a mirror bot, how to play this optimally. This is probably similar, but you may want to duchy a little more aggressively - or at least, that's what consensus seems, though I'm not sure I see that much of a difference myself...