I think with Scepter and/or Capitalism there are many more loops.
For example:
In play: Lurker and Smithy
In hand: Watchtower, 2xScepter, Potion
On deck: 2xScepter, Potion
In trash: Mandarin
Loop: play Potion, Scepter as Smithy (drawing 2xScepter plus Potion), Scepter as Lurker gaining Mandarin, topdecking 2xScepter and Potion, revealing Watchtower to put the Mandarin back in the trash. Now you're back at the starting position, except one potion richer.
Use Hunting Grounds instead of Smithy if you want to draw your deck. Use Council Room if you also like buying things, and use a Copper or an extra Scepter for money instead of Potion every now and again if you want to buy nice things not named Vineyard.
Lurker, Hireling and Bonfire can set up almost any situation fairly easily if you're a stickler for guarantees (against passive cooperation).