Geraint, I think you got right to the heart of the matter in one. I strongly suspect that the patination on these is not going to be reliable. Isnt this something easily cured with the right chemical concoction, however? (edit: though, alloys are probably just as important, perhaps more? I wanted the work done in shibuichi, but he wasnt comfortable with making it, prefers to work in copper and brass I believe.)
Well...he didnt do them for free, and there was quite a lot of communication and double checking required. Also, there arnt that many people around that can do the work to a decent standard.
P.S. Is that a quote from the book your great grandchildren will write a hundred years from now? Haha... I cant imagine the demand from western sword collectors being THAT high, but then again, what would stop eastern collectors from going the same route...?