Being the only eink reader with Xwindows support, we could benefit from a lot of arm ports... if only we were able to find them. Main issues are kernel compatibility and glibc (plus other libraries, perhaps) compatibility.

A good started point I had missed before is the OpenPsion website. For instance, they have a HowTo pointing to other resources:
http://www.openpsion.org/howtos/netbook_new/x439.htm