When it is your turn to send a VASSAL move, the wait is excruciating. When it's my turn, well, I've been busy.
I have not seen a VASSAL module, I would certainly like a copy if someone has one. As it is the rights to the game are the property of Decision Games and they won't allow VASSAL modules to be distributed. I hear they have another interface that they do authorize but I don't see it listed on their website.
As far as the other question. The game is almost completely unplayable by email. I would never consider it and I do play a fair amount of email games.
The problem is basically every time you move next to an enemy unit you have to stop and the enemy either says 'counterattack' or 'go'. A very interactive game.
Ah, then in that case the question is moot - although could be played real-time VASSAL.