I signal this game http://www.real-warfare.com/

Barn Allen on outofeight gives him a good rate http://www.wargamer.com/article/3121/pc-game-review-real-warfare-2-northern-crusades

The better is the great moddability of engine; the game is interpreted using a metalanguage and the editor included is the same used by the developers

I have created my little mods amusing my self to improve the realism of battlefield mechanics and AI unit reactions

Just curious, how is this different/better than the Total War games?

hardware requirements is lighter that total war (2,9 giga, run also on low specs PC).
tactical battle is similar but more realistic (the programmers derived it from the rules of Napoleonic boardgame), especially moral and ground are more important factors.
the strategic campaign is in realtime and in M&B style (I don't know if you have present how it is), not in TW style; is very hard and well made.