This is such a regular question on aikiweb (including once by myself). There are a new set of Saito books (Takemusu aikido?). But the old traditional aikido (weapons) books are out of print and impossible to get hold of - lucky I've got trad aikido 2. Many groups in the U.S. seem to operate on a different set of kumitachi now as well, don't know how that came about.
Maybe we should get together and ask the publishers to reprint them! I would definately buy all the other books on the series. Also, the Takemusu aikido books are really difficult to get outside of the U.S. I contacted one person in the UK, but they never got back to me. You could try Aikido on-line if you have a credit card, and pay in dollars.