... the real winner here is probably Conquest, as it is only limited by our money+buys.
The best way I can think of to get lots, but not infinite money, is with Priest/Fortress/Watchtower and Travelling Fair.
Kudos to Bitwise for suggesting Conquest. It is an excellent way to acquire VP, granted that you can buy the event many, many times after acquiring all of the Silver in the same turn. I worked on an alternative to using Priest and trashing to generate coin. I decided to just use Copper!
In a nutshell, it went like this:
King's Court a ton of Coppersmiths (with the help of Overlords, Band of Misfits, Inheritance, Crowns, and Scepters)
Play 52 Copper for a ton of coin
Buy a Mandarin; Coppers all return to deck.
Buy a Villa
Play a Messenger; Coppers go to the discard pile
Play a Counting House; Coppers go back to my hand
Repeat.
I managed to buy Conquest more than 10,500 times for ~420,000 VP.
How does this compare to Bitwise's strategy? I decided to flesh it out more to find out.
TO BE CLEAR, this strategy has all been suggested by Bitwise. Use of Priest, Forge, Mandarin, Villa, Crown were all spelled out by him. I just put it all together in a (hopefully) optimal implementation.
The kingdom will have:
Platinum/Colony
Action cards
Priest
Fortress
Forge
Mandarin
Villa
King's Court
Overlord
Band Of Misfits
Scepter
Crown
Young Witch
Events
Delve
Inheritance
Ferry
Pathfinding
Lost Arts
Seaway
Training
Travelling Fair
Projects
Capitalism
Sinister Plot
Setup to be done before the megaturn (in no particular order):
Ferry on King's Court (allows play by Overlord)
Inheritance, Pathfinding, Lost Arts, Seaway, and Training on Priest (it ought to be Pope by now!)
buy Capitalism
buy Sinister Plot
Acquire
All the Priests
All the Overlords
Other than leaving the Silver, Mandarin, and Villa piles alone, buy everthing else you can without emptying a third pile.
Acquire sufficient tokens on Sinister Plot to draw your entire deck.
Megaturn:
Trigger Sinister Plot to draw our entire deck.
(Every time we play a Priest, we will trash a Fortress, so that will not be mentioned again.)
(action phase)
Play 9 King's Courts and 8 Overlords as King's Courts
Play 10 Priests, 2 Overlords, 10 Estates, and 9 Band of Misfits as Priests (3 times each).
The 1st time we play a Priest, we get 3 coins
The 2nd time we play a Priest, we get 3 coins + 2 coins for trashing
The 3rd time we play a Priest, we get 3 coins + 4 coins for trashing
The nth time we play a Priest, we get 3*n + 2*(n-1) coins
[Priest has been played 93 times]
(treasure phase)
Play 8 Crowns (saving one), each playing Scepters, replaying Priest each time.
Play the last Scepter, replaying Priest.
[Priest has been played 110 times]
(buy phase)
Buy Mandarin; all Priests, Crowns, Scepters, Villas that are in play are put on deck.
Alternate Priests and Crowns on top, then remaining Priests, then Scepters.
Buy Villa
(action phase)
Play Crown on Fortress; draw a Crown and a Priest
Crown the Priest; draw another Crown and Priest
Repeat until you draw the last pair, then just play the Priest (saving the last Crown); draw another Priest.
Play that Priest to draw the last Priest.
Play the last Priest to draw a Scepter.
Play Scepter to replay Priest; draw another Scepter.
Repeat until you've played all Scepters.
[Priest has been played 137 times]
Buy Mandarin, Villa, do it all again.
On the 8th iteration and beyond, we do the same, except we save one Scepter along with the one Crown.
On the 9th and 10th iterations, we do not want to play our last Fortress, so we Crown the Scepter instead to replay a Fortress twice.
After we buy the last Mandarin and Villa, the loop stops. We play all of our Crowns, Priests, but not Scepters for the last time.
Priest has been played ~350 times for about 1,750 coins and 350 buys. Trashing a card gains ~700 coins.
Our hand now contains:
{10 Mandarin, 10 Villa, 9 Forge, 1 Fortress, 1 Scepter (others are on deck), 9 Young Witch,
52 Copper, 29 Gold, 11 Platinum, 7 Duchy, 7 Province, 7 Colony, 9 Curse}
Play one Forge and trash everything left in our hand for 161 x 700 = 112,700 coins, bringing our total to around 114,450.
Buy Delve 38 times
Use Travelling Fair to buy Conquest ~14,300 times for ~572,000 VP.
And thus my strategy has been beaten. Curses Bitwise, I have been foiled again! (good job)
You also mentioned Lurker, but it becomes possible to repeat the iteration an unbounded number of times.
Something like: Crown Scepter, replay Priest twice, trash Mandarin, trash Villa.
Crown Scepter, replay Lurker twice, gain Mandarin, gain Villa.
I suppose this could be sufficiently crippled by limiting the draw into the hand, but I'm busy working on a different scheme.