I recently designed several themes for a website. To simplify my naming process, I decided to find, like OP did, an already defined list of names and ended up using Paris' Métro stations [1].

Some examples:

  - Alesia
  - Concorde
  - Dupleix
  - Exelmans
  - Madeleine
  - Pyramides
  - Solferino
  - Trocadero
  - Voltaire
  - Wagram

As a bonus, you can use the Métro lines' color to visually identify your themes (or hostnames).

[1] http://en.wikipedia.org/wiki/List_of_Paris_metro_stations