As Joe P probably knows, the solar panel is an "option on an option"; You have to order the large sunroof (I forget the sales name for the big roof, it's the same looking sunroof that you can get on the C230 Sportcoupe) before you can get the solar panel option. The solar panel is actually located on the large fixed piece of glass on the rear half of the roof.
BMW has also offered heated steering wheels. YES, they feel great in the winter. My BMW cycle is also equipped with heated hand grips, and BMW is also offering heated seats on their motorcycles now, too. (maybe on my next bike