Speaking hypothetically, it would be relatively easy to implement a variety of abstracts for Vassal. For example, using just the black stones and white stones from the Go module, and various boards, a module “Two stone games” [size=150]could[/size] be created.
Here’s a list of candidates: *Star & Star Y, Atoll, Breakthrough, Catchup, Connect6, Crossway, The Game of Y on a triangular grid, Go-Moku, Gonnect, Havannah, Hex & Quad Hex, Hexade, Oust, Pex, Slither, TriGo, Unlur, and Trap Y. See this post on BoardGameGeek.
Would anyone be interested in actually playing these games using Vassal? Most of them are already implemented on Game Center for real time, or Little Golem or Gamerz for turn-based or email play.