Here is a link to the dock on Engadget. Looks like it'll go for 100 US dollars, but that is pretty good deal for all that you get in it.
It looks pretty sleek. Probably a good match for the Mini's good looks!
It has a DVD-CD drive, 2.5 in. SATA drive or SSD drive, and it works well with Windows XP or Vista, but no word on Linux. It look s pretty nice though.