Actually, you guys may be the only remaining active Dikurivative maintainers. ROM is dead, and I only see people trying to C++ify it, not really evolve it. I guess Circle is still around in the hands of the TBA people. I see them release something every so often. I remember an ACKfuss, which may still be around. Are there any others?
On the LP side, Dead Souls is the main contender for FluffOS. Gurba keeps up the DGD end. I haven't seen any public release of a mudlib for LDMUD in years.
Are the TinyMUSH people still around?
That's all I can remember of the "old guard". There are some newcomers using ruby/python and such, but so far most of them aren't ready to build a production MUD with. I might be wrong about NakedMUD, haven't looked at it in a while...