Aye, yeah, I started something like that awhile ago. I heard the idea first from some SCA guys down here. My pieces went something like this:
Shield Blue
Single Blue
Dual Blue (Could attack twice)
Red
Archer (Ranged)
Javelin (Ranged)
Spear
Smashing (Mace/Hammer/Flail)
You also got two Knights, which could be declared as Single Blue, Red, Shield Blue, or Smashing, and could be moved 1 more space than the normal fighters of the same name.
EDIT: And you had a Lord, which was the basic "King" (from Chess). Later, some friends and I renamed it to Commander, to make it more ambiguous and less affiliated.
It worked, but I kind of put the project to the side. I still have the drawings up somewhere. If I can find them, I'd be happy to scan them into my computer and upload them. Feel free to build off the ideas I presented, but if you use the drawings, please give appropriate credit.
We tried using it for "battle plans". That went a lot more smoother than actual chess.