Flog me if I screwed up, but I don't think I saw them in bavarian autosport. Anyway, I *MIGHT* be thinking about installing either the factory rails or a ski rack on my '92 525iT. It has very clear places for such an aparatus to hook into, but there's rubber weatherstripping like stuff in its place. I also looked through pacificbmw and vinesbmw's web pages, found jack. I may not be able to afford any of it, but I thought it was worth looking into.
After finding out that the shade to hide your stuff in the back would cost 700 bucks to replace (mine won't retract, but I can either fix it or cope.)retail, 500 wholesale, I'm not expecting those rails to be cheap. :)