Sometimes it just takes a lot longer than what I initially planned ... I finally managed to fix the problem with the Perfection 610 color channel shift (or whatever this "feature" should be called). The fix was pretty easy, the problem just was that by implementing the algorithm I made a very stupid error and it took me two days to figure our what I did wrong. When I scan thin black lines I actually get thin black lines and not three colored lines right next to each other.
On a different but related subject: The USB problem with EPSON scanners is also finally fixed. Thanks to David Nelson and everybody else who was involved in comming up with the proper way to handle the USB scanners. The new scanner driver is in kernel version 2.3pre7 and newer.
There is also some news from the color management corner: I created a small Gimp plugin that can be used to apply input (scanner) and output (printer) profiles to an image. The scanner profiles can be generated with SCARSE, for the printer profiles I'm using a commercial package. The plugin can be downloaded from my site.
The plan for the weekend is to clean up the Perfection610 software a little more (there is some garbage on the first and last few scan lines) and to implement the soft proofing in the color manager plugin.
For the long term I'm looking for people interested in color management issues. I hope to get a small group together to work on stuff like a printer profiling package and a solid color management for Gimp.