Hi Paul,
I can't claim to be an expert here, but you might find an interesting answer to your question in one of the maxims of the International Hoplology Society: "one mind, any weapon." The founder of the IHS was a koryu kenjutsu practitioner, as are the people currently leading the IHS. They have all believed that the point of true military training arts is to teach fundamental combat principles that apply to any weapon.
A great example of this is the way that many koryu schools have almost identical kata for different weapons. In an essay in one of Diane Skoss's books, Liam Keeley describes how some of the sword kata for Tatsumi Ryu are almost identical to the Tatsumi Ryu short staff kata or the kodachi kata, with only minor variations for the changes of the weapon. The idea is that someone who truly understands the fundamental techniques that lie at the core of the school should be able to apply those techniques with any weapon. Will a technique for a katana work perfectly for a dao? Maybe, maybe not: there will be differences in balance, cutting ability, etc., that you might have to adjust for. But the basics facts related to cutting a human-sized target with a sword won't change. Perhaps a technique that depends on the curve of the sword wouldn't transfer well to a straight weapon. Perhaps when fencing Western-style and using huge lunging thrusts one will have to radically adjust concepts of maai. But at the end of the day, you are still using a sharp piece of steel of a certain length to inflict damage on a human body, and there are really only so many ways to do that.
Just my .02. Though with this economy, I'll be lucky to find someone willing to pay that much.
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.