Here are a number of links to other Tolkien-based MUDS, Tolkien resources, and Mu* Resources that you may find useful.

Multi Users in Middle Earth (MUME) -- An excellent Tolkien based MUD and one of the oldest. This is the MUD many of the original players and builders of MEM got started on.

Elvenrunes -- A MUME fan site and excellent Tolkien resource. Also an entertaining Mud gaming community.

Return of the Shadow (RotS) -- Another good Tolkien based MUD, also started by former MUMErs, RotS is set in the fourth age of Arda and centered around Mirkwood.

The Shadows of Isildur -- A roleplaying enforced Tolkien based MUD.