Maybe it is easier to port
DjVuLibre to use framebuffer? Realistically, the Kindle can run lots of framebuffer apps with little or no adaptation (I got links2 running the other day). The main issue is that people still want their Amazon features (free WWAN, buying books auto-delivered and whispersynced). Otherwise there's no reason we couldn't load Ubuntu ARM onto it with a little work on a keyboard driver for X.