Empires in Arms is a great game - I've never played, but did observe a long-running game at a game shop back in the day. They had a wall-mounted version with magnetized counters. The crew met once a week, so every time you walked into the store you could track the progress of armies across the continent. Good stuff.
Likewise with Warfare in the Age of Reason. Dale Wood and Tod Kershner were my wargaming mentors back in grad school. Great guys, and someday I need to put together my own table for AoR as a tribute to them. For terrain battlefield terrain I'm using a mix of real-world meeting grounds and pre-built terrain mats with the latter informing the former. Once you see the map of the imagi-nations it should make a lot more sense. A bit of a kludge, but my own terrain collection has to be part of the equation for deciding how to organize things.
How well do you think the board games you recommended would work for PBeM campaigns?
In the end, I decided to go old school. I whipped up a map and threw together a sort of Diplomacy style rules that will make it easy for the players to just email me orders that I can adjudicate. I'll be tracking everything and informing them of the results of each turn here:
http://trossianwar.blogspot.com/