Shogun 2: Total War was a pretty epic return to Feudal Japan, but it looks like Creative Assembly is going to outdo even itself when it releases the standalone expansion, The Fall of the Samurai in March next year.
Fall moves the action into the 1870s, when old Japan was rocked by ongoing contact with the colonial powers of the Pacific, namely England, France and America. If you want an idea of what happened when rifle-powered armies met stoically reserved Samurai in battle, you might want to watch The Last Samurai (despite Tom Cruise).
Or, you could watch this trailer, which sums it up pretty nicely. The game's going to be huge, with new Japanese factions, the colonial powers, and of course a raft of new, modern units.