Ideally, the beige SKS Longboards are probably the way to go:
http://www.sks-germany.com/?l=en&a=p...0437&LONGBOARD
I think silver would be a nice complement to the bike, as well. With such big, blackwall tires, I feel that a black fender would just exacerbate the visual heaviness of the wheel.
I would not suggest to paint them, as I think that, in the long term, it would be difficult to maintain a nice appearance.