So, a PBEM? Or is there some other way to do this that I'm not aware of...?

Sounds like fun. Question, though: How will you define "blitz" and "turtle"? Seems like the "rules" for the different playstyles would have to be made explicit.

Is the turtler allowed to take nearby rebel provinces? Can he initiate wars, or only respond once attacked? Is there any limit on the turtler's rate of expansion -- one new province acquired every 20 turns, for example?

How much is the blitzer allowed to tech up? Must he play the entire game only with units initially available?

Essentially, at what point in the game do you stop being a "blitzer" and start being a "turtler", and vice versa?

Ultimately, I see turtling as a way to allow the AI to tech up -- turtling is a way to purposely make the game *harder*, whereas blitzing is a way to make the game faster and easier. My money's on the blitzer, even though I find that style less enjoyable when playing against the poor AI.