Thanks to xChrisx for the advice how to do it! (And thanks to Shannon Brown for the Felynes, on which it is based.)
Here is a simple race with extra travel:

http://dragonprime.net/users/eph/racecentaur.zip

The amount of extra travel a centaur gets is admin-configurable, as is the required DK amount.

Centaurs share a city with humans.

(German translation available with the Translation Wizard. The Mine text is still missing though.)