It looks like Mikio Hirabayashi, the author of Tokyo Cabinet is moving along and started developing the successor of Tokyo Cabinet. The name of the new project is Kyoto Cabinet. The project web page  looks extremely similar to the one of Tokyo Cabinet .
By comparing the declared goals of the two projects and the rest of the (scarce) documentation, the only major differences I could find are that Kyoto Cabinet is written in C++ and that it aims of supporting non-POSIX systems.
While Kyoto Cabinet is still in alpha, I cannot wonder what is the future of Tokyo Cabinet. Is there a community behind it to at least take care of any major bugs and help with the migration when Kyoto becomes more solid? (note: I tried to contact Mikio Hirabayashi but I haven’t heard back).