The walmart near me twice (both times it was there for over a week before it was removed and eventually replaced, granted the enclosure isn't the best at venting heat. And the gamestop near my house once, this one had a nice enclosure though.
I also know a few people who've had their 360 RRoD. So either my experience is an outlier among outliers or it really is a widespread problem.
RRoD issues was one of the reasons I didn't purchase a 360 last year actually. But thats a whole other thread.