What about the Battlefield 1942 / Battlefield Vietnam / Battlefield 2 series of games. Might suit the idea quite well. You can have a lot more missile based combat...but I don't really know how well it would do powerful hand-to-hand combat.

The earlier series has a very mature set of tools and is pretty well documented. BF2 is a lot more complex to mod, but is graphically a lot prettier.

You don't, of course, have all the tactical and strategic things that RTW has to offer!