Hey guys. I'm known fairly well on the Koei forums as a historian for the 'Romance of The Three Kingdoms' so learning about this mods existence was pretty awe-inspiring for me to jump in. Unfortunately I cannot directly offer you my aide, as I am currently working on a warband overhaul project with a few friends, but I know everything to do with China concerning this time period. I've also browsed the boards and it seems that a lot of you have read only the book or played the games, neither of which are really that accurate to what happened according to the chinese archives.
Guan Yu and Zhang Fei for a start should never even be considered as companions and Guan Yu has to be made crap in comparison to Zhang Fei. I am sick of the book being 'Shu-centric' and the games being 'OMFG, GUAN IS EPIC' and your Han empire list doesn't look right at all from a logical 'characters' point of view.
I can help with what actual weaponry, armour and what-have you was used, please don't use guan dao's, they didn't exist in this time period and before anyone claims that Guan Yu invented that he did, that's purely mythical and also he had a dagger-aze not a guan dao for anyone who tries saying otherwise.
Good luck either way and if I do get time I'll help where I can if you want. I am a texture-graphic designer/history freak.