MUME now has a number of "subraces" for some of the races.

Elves
  Silvan (2.5)
  Sindar
  Noldor (3.5)

Hobbits
  Harfoot
  Stoor
  Fallohid

Men
  Dunedain (1.5)
  Boerning
  Eriadorian      <-- that's common Men
  Rohirrim

Trolls
  Cave
  Hill
  Mountain

Currently, the only differences are in the aging factor, and the initial 
languages you know (the languages have changed a little, check 'cha lang').