Xconq is the "
Penultimate Strategy Game". It's not actually a game, it's a
framework for designing
strategy games. xconq allows design of any sort of
hex-based or
square-based strategy game, and comes with all sorts of
scenarios made with that engine - from clone of
empire to
Godzilla scenario and clone of
Civilization 2.
Now, if only I'd get BattleTech for this...
http://sources.redhat.com/xconq/