Trading my 645Ci 6-speed for the M6 and am on waiting list in Canada. Gave deposit in January. Dealer says sometime between March and September '06. Not crazy about the color choices so I hope there may be some additional ones by then. Sepang Bronze is the best of them I think.
I like the color of my 645 (Stratus grey with cream leather and elmwood interior), and might just spec it as an individual color on the M6. Resigned to getting SMGIII rather than wait an indeterminate time for the stick.