Here are some historicals to cleanse the pallet before I hit you with more fantasy stuff. I have been working on some Ashigaru to add to my 15mm Samurai army, and stumbled upon these old pics.
I went through a pig Samurai phase back in the late 90's, and have revisited it from time to time since then. A Short History of Japan, is one of my favorite pod-casts, and usually inspires me to paint a unit or two every few months.
Rather than focus on Clans, I painted these armies into color groups. There is a Red Army and Black army as the primaries. (Check out the Japanese film Heaven and Earth for the proper inspiration) And then blue, purple and yellow groups as auxilia/allies.
I, of course, have plenty of Daimyo to duke it out, or switch sides with reckless abandon.
One of my favorite forces are the Ikko Ikki and other warrior monks.
I used to use these with the Killer Katana rules, I'm not sure what the rule-set of choice is today.