I bought a couple weeks ago a Sheevaplug, and after struggling a bit to make it work the way I want,
I'm here to report a fully functional Bittorrent Seedbox!
Based on ubuntu 9.04/rtorrent/rutorrent, works like a charm!
The hard drive used (powered only by the usb port) is a WD 120gb sata 2.5" fitted in a small aluminium usb case.
Guess a bigger hard drive wouldn't spin, but that's big enough for my needs
Just here to share the experience, I could actually try to write an how-to about it, maybe someday
If anyone needs suggestions, I'm here.