I wonder how feasible a simple multiplayer roguelike map would be, using the custom map editor and some incredibly amazing map-making skills? I know scripts can modify the map and do all kinds of wacky stuff. Take a look at some of the RPGs out there, and the various LoTR based defense maps for example.
Remember folks -- you heard it here first
I don't propose that this replace MAngband at all, since it's not free. But, I'd play a roguelike map if it existed and was good.