Ive never seen one on a Seat, you should be able to get an aftermarket one, you can get anything at a price.
Just been looking for bits on ebay and spotted a camera that replaces one of the number plate lights
http://www.ebay.co.uk/itm/Seat-Leon...2?pt=UK_In_Car_Technology&hash=item3cc1a821a8
Looks like a good solution. I may consider it if I can find out if it will work with my Pioneer headunit
Search my thread. Seat reverse camera badge. I've made my own