I helped NorCal take his car over to Peter Pan today for a slew of new upgrades. While there, we were looking around Dana's parts palace, and we noticed that BMW now has some new wheel caps with a chrome ring that fills the entire hub hole instead of the old ones that have a gray plastic lip. Without the plastic lip, the roundel portion of the center is now slightly larger, and it has a greater convex relief (compared to the old one that's fairly flat). In short, they look MUCH better.
Part number looks to be 36 136 783 536 (not sure if this ala carte or for a set). I grabbed a set, and they're already on my dirty car.