There are some STW mods. Whether they are good or not depends on your definition of good. I just checked the website and didn't see any. I seem to remember Barocca knowing of Shogun mods, and I think he created a nice one some time ago. Trying contacting him via a private message here.

If you have Medieval TW Viking Invasion (VI), there is a very popular mod for it called Samurai Wars. It has been completely overhauled by some of the best modders around here, and players still meet online occasionally to play multiplayer battles, and have even conducted mini-tournaments. Puzz3D would be the member to contact about this MTW mod.