For a martial artist class, in an ideal world, I would adapt either Blood & Fists, a d20Modern product written by Charles Rice and published by RPGObjects or the system or 2e Complete Ninja's Handbook (slightly revised from 1e Oriental Adventures) along with some related articles from Dragon Magazine. Both give systems for creating new styles with a variety of maneuvers, stances (I think there was an article for the AD&D system giving stances) and special abilities along with many examples of styles.
If going with the former, the book was good (and, imo, the bes MA sourcebook for d20/D&D), I would then go through through the Master Edition, fixing some of the styles brought in from the Hong Kong Knights (e.g. why did the new styles not get signature maneuvres). I also want to address why that some of the signature maneuvers from the original book are found within some other styles. I also need to fix a few styles as I know that they are missing several maneuvers (e.g. Arm Lock) shared between Hapkido, Hwa Rang Do, Jujitsu, and Kuk Sul Won, but missing from the Korean styles before going through references on some of the other styles to see what (if anything I can find) has been missed.
If adapting the latter, it has a few of its own issues to address before adapting.
Either way, I would also go through GURPS Martial Arts, Ultimate Martial Artists for possibly more maneuvers and special abilies (probably, both Ninja's & Superspies and Mystic China, for more special abilities (not the styles). Then I would go through several books,magazines, and websites on specific styles.
At the moment, I am wishing I did not give several of my old Black Belt, Inside Kung Fu, and other MA magazines from the 80s and 90s to my old instructor and sell/trade part of my marital arts library to a used bookstore.