I would suggest getting your black belt in Kenpo, I know I wish I had and at the same time do not break off any ties with your Kenpo school as Kenpo is more of a "I really want to win/survive a street fight and need to get as close to what real unarmed combat will be like" where as the "Ninja" are more of a "No sparring allowed; this art is too dangerous (provided you have a sword and the other guy doesn't have a gun)."
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If you are looking for "Ninjutsu" to be a "Warrior's Art" it kind.... of is, but in a very classical sense (to me). I feel that if you are looking for a system that promotes the warrior ethos and is geared toward survival just be prepared to put a significant amount of time to get to a level where you have enough practical skills to be useful. BBT really seems to be about teaching skills that are too archaic to be practical in todays society and if you are in the military and prone to deployments you might want to do some distance ed/videos first to see if this is really what you want.
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Sorry for the long windedness of my reply but Kenpo v. Budo Taijutsu would put Kenpo hands down as the better of the two and a strong foundation in Kenpo might save your life whereas as too much BBT might or might not help (personal opinion only).
My experience has been vastly different.