Keep in mind that ranks above Godan are best understood in the context between Soke and the person who the rank was given to. As for the charge for the rank, I would believe that would be at Soke's discretion at well. Also keep in mind that while the fees required for some Dan ranks may be higher than in some schools (some, not all), there is no official testing below Godan, so that is something to take into consideration in the long term.
Bujingodai:
I realize you are now with an independent org, but keep in mind that the Bujinkan Hombu respectfully requests that tuition and fee info is not supposed to be posted, partly because these charges can vary depending on where you train. However, thank you for the info.
Kreth:
I do not know of the actual case you speak of, but possibly the individual and Soke Hatsumi had a special arrangement in regards to the cost? He does have the ability to do such a thing, and I would not be at all surprised to find that it has happened in the past.
Greg Chapman:
Its good enough for me, my teacher is a registered shidoshi with the bujinkan, he teaches me bujinkan, i learn the knowledge, that's good enough for me
I understand your sentiment, but don't you feel that the organization that is the source of these techniques deserves their due (or dues, in this case) as well? If you were a teacher, and one of your students was teaching someone else your techniques without your knowledge, and without giving you any compensation, how would you feel? Also, is your teacher
currently registered (if you are not sure, just ask him to show you his most recent Shidoshi-kai card)? Just because he achieved the Shidoshi title once is not a guarantee he still has it in the eyes of the Bujinkan. If he is not a current member, he may also not be privy to anything "new" coming out of the hombu dojo in regards to techniques and principles (not new techniques as far as age, just as far as emphasis). Just so you know, if your teacher is a current Bujinkan member (i.e. he is in the Shidodhi-kai), and you plan to test within the Bujinkan, when you go to test for 5th dan (which very well may be with Soke himself), you may have a bit of an issue providing documentation of your previous ranks - if, however, he runs an independent dojo, than this may not prove to be an issue, as you would not be testing at hombu. This may not be of concern to you, but I figured it was information you should have.
Also, if at all possible, let's try to keep everybody's "toilet habits", including their preferred reading selections while so engaged, out of this. For those who are interested, I'm sure rec.martial-arts has plenty of information on the topic already.