Finally got a chance to take some pics. These are factory 18" wheels and tires taken off an E70 brand new and sold by the dealership as "dealer take off's." They sold them to a guy who sells wheels on ebay, and I picked up the set for $1295. I've always liked 5 point rims, and IMHO these look great on the X (just not as mean as the 20's of course ;-)
After reading some posts on the board, I was concerned that the wheels wouldn't clear the large 4.8is front brake calipers, but with this style rim it turns out that there is plenty of clearance, even enough to slide a deck of cards between the rim and caliper.
First three pics are "before" with factory 20's. Last three pics are "after" with factory 18's. So far the ride is great, the handling is excellent, and the X is killing it in the snow.
The dealership charged me $40 to swap out the wheels. Because the tires had originally been mounted and balanced by BMW on the E70, they billed it as a tire rotation and it only took them a matter of minutes.