You can order the speed-loaders here:
DS-10-SPEED is a custom made speed loader for S&W 617 10 shot revolvers. - Windows Live
I have to say they work great. Order lots of loading blocks, they can make your range experience a dream.
With the speed-loaders and loading blocks full, plus 10 in the gun, I have 330 rounds at the ready but they tend to go very quick