What amazing news! I do some web searching for a simulator and I discover 123D.Dircuits.io! It is a simulator that seems to be all but specifically designed for the purposes of playing Circuit Wars! It appears to allow the placement of multiple processors, the simulation of their code, and analog circuit design as well. About the only missing from this picture is a two-person interface and that can be solved by referee or by remote control of the web interface.
If you trust the other player you can use TeamView and if not you can use a neutral computer. This is a very exciting development for the game! more to follow!