Colorless commander using lands that chose based upon identity?
The rulings under the card in Gatherer say


  If your commander is a card like Kozilek, Butcher of Truth that has no colors in its color identity, Opal Palace’s last ability produces no mana.


That means you can use it in your deck but it won't produce the desired effect.

Exotic Orchard has no colors in its color identity and can be used as well, and it works just as it would in a normal 2 player game, i.e. it can be used to produce blue mana if your opponent controls an Island.