The Lord of the Rings Rules variants Yahoo Group has a set for Napoleonics.
Isildur’s Bane is a set of free wargames rules for playing solo games of the Lord of the Rings Battle Game.
Legends of Old Mars is a Edgar Rice Burroughs’ Barsoom variant of Games Workshop’s Lord of the Rings / Legends of the Old West game. I think that system is perfect for playing games involving John Carter, Tars Tarkas and the other denizens of Burrough’s Barsoom.
Here’s a variant of Warhammer Ancient Battles for the American Revolution. No. Really. It could work.
Games Workshop’s Lord of the Rings system proves to be remarkably versatile, as gamers have adapted it to a large number of skirmish periods.
The Vietnam variant of the Legends of the Old West game is available at the Lord of the Rings Battlegame Yahoo Group.