If you want to get more replies, you might try directly contacting some of the koryu scholars who no longer post here. Meik Skoss has been very helpful the few times that I've emailed him with questions (you can find him occasionally over at Swordforum). Also, you might consider tracking down a copy of David Hall's dissertation; not only is it more than worth reading on its own, but the citations would give you a huge number of good Japanese-language sources.
David Sims
"Cuius testiculos habes, habeas cardia et cerebellum." - Terry Pratchet
My opinion is, in all likelihood, worth exactly what you are paying for it.