Sequential shifting is being looked at by all the major companies. JBsC5 may find this particularly interesting as he's a Vette driver (which I was until I lost my '99 C5 coupe in an unplanned road engagement).
A couple of years ago I attended the Bragg-Smith Advanced Driving School in NV (the Corvette driving school). There were a number of Corvette engineers and designers taking the class. A Powertrain engineer said they had bought a Ferrari with the F1 shifter and had been studying it for inclusion of a similar system in upcoming Corvettes. The problem was (is?) reliability. For a mass marketer like GM -- and to a lesser degree BMW -- any transmission has to be as reliable and bulletproof as any automatic currently available. Besides the issues of cost, the reason these trannies are appearing in very high end product is that the companies need experience in determing failures and repairs. As they gather information, they're able to come up with more reliable systems that filter down to the "average" driver. Now of course, no one on this forum is an average driver but BMWs are often purchased by folks with no particular aptitude or interest in performance driving -- heck, they don't even read the handbook. To some degreee sequential shifting requires the driver to re-learn how to shift. It's not a conventional shifter and its not a traditional automatic. So you have to figure there will be some driver "error" as part of the learning curve and the companies need to be able to protect themselves from potential liability (remember the Audi A5 debacle?) by showing that previous drivers in high end or speciality cars didn't have such problems, and that the blown transmission was not because of computer error by rather operator error.
When you consider that even on a sports coupe like the 330CI only 20% come to the US with stick shifts, you realize the potential problems BMW might have introducing SMG to a very large driving population. Of course, if anyone has ever used one of these F1 style transmissions they're instantly transformed into believers. I would've gladly paid a premium to get one on my 330CI if it had been an option. It's truly the best of both worlds. I guess I'll just have to wait for SMG to "trickle" down to the rest of us.
