This is the only other one I am aware of. They also do the side pod (seat fairing) bags that velcro to the frame. Useful for tools and chain etc. I think they call the liners the "saddle bag liner" near the bottom of the list.
http://www.motobags.com/bags.shtml To be honest though, we used the Nonfango hard luggage on the ST in France and it is fine. It unlocks easily, is quite easy to carry into a hotel etc. Can't remember them leaking, and it did rain too. A lot.
Or, you could use Tesco bags.
[Edited on 12-4-2005 by HW]