Can you give me a specific timeline for the scenario? It'll be easier for me to research some stuff. As for the map, I don't think such statistic exist or was even availible at the time. Apparently any basic census was done during the Tokugawa regime, but not before, so its probabaly impossible to find any written work on it. I've spend an hour or so at the libarary and nothing of the sort comes up. I'll try asking the libararian, but I doubt they'll actually know anything. I do know, however that our libarary have Map of Japan for government record and stuff which mean they are probably really accurate. If you need it, just tell me and I can check it out.
Edit: i did a search on the web and found a interesting forum thread, you should check it out.
http://forums.totalwar.org/vb/archive/index.php/t-3919.html
Anyway I found a couple interesting book and one of which deal specifically with the Protugeese's arrival in Japan and the Teppoki and its spread on part of Japan. And there is list of Kanji term with Teppo-Tai, which translate to Rifle team should work as one of the name for the early rfile units.
And as for Art and Literature, Muromachi is actually consider one of the more refine age where suiboku painting, landscape gardening, and tea ceremony were perfected. Since I take it that the scenario starts on the late Muromachi-age, these should be things to think about.
The Muromachi Religion focus mainly on the emergence of Zen buddhism and Nichiren along side Shingon and Tendei, all of which incorporate aspect of horsehockeyoism. In effect, there is no actual religion base solely on horsehockeyoism till Tokugawa era.
Daikan-Deputy or supervisor ( I think this should replace the word Governor in the game..if possible).
I also find a map of various "county" of Japan during the Sengoku Jidai that is color code to specific warlord. I'll scan that in the next day or two and PM it or just post it here.
Edit: This is a website for the mod of the game Shogun : Total war, no idea what it is..but the site contain some very interesting informations.
http://www.darthveda.com/sengoku/clans.html
There is also a map of Segoku Jidai Japan but are not very accurate I believe especily the ronin and the Usesugi part
I also suggest that maybe make the Koga and Iga a stand along country, because during the Segoku period, they are basically self-ruled. I was thinking that their should be a generic ninja which all Daiymo can use and clan-specific Ninja that you can only build after trading with either the Iga or Koga,which is like a one city countries, for the so called "Ninja resources" or you could be like Oda just conquear the area with overwhelming forces and claim the resourc to produce your own Ninja. Or you can pay and negoiate the clans to fight for you. This is my excuse for using all the Ninja units made on the forum. XD