Hello beav,
You could also look for the MIniHobbyModel kits. They have a IX-B and a IX-C.
These kits are exact copies of the Nichimo kits, and build into quite nice
models.
Another kit is the Academy IX-B. This kit is a motorized non RC toyish diving
u-boat. The hull is quite accurate and very detailed but all the diving mech
will have to be removed and the propulsion system will have to be rebuilt.
You will have to add double drive shafts, rudders and propellers as well as
rebuilding the fore and aft dive planes. With a little patience, it will build into a
very nice type IX. The tower will also need to be modified from a B to a C.
Have a nice day and happy modeling,