Do you want an all white wheel? I don't think I've ever seen anything like that and it would probably have to be painted. Next best option is wheels with color caps.
http://www.wheelspecialists.com/inde...gdetail&id=208
http://www.wheelspecialists.com/inde...=gdetail&id=54
http://www.wheelspecialists.com/inde...gdetail&id=488
Those are the few that I could find on that site. I'm not sure how you feel about chrome, because it seems that almost every wheel with a color matched cap these days comes with the chrome lip..