I guess the easiest way to do this is just list out requirements.
- E-Ink (or equivalent)
- Linux or Android
- Rootable if Android *(1)
- Allows me to install Amaze and FBReader from APK *(2)
- Backlit
- Decent amount of space or microSD expandable
1 & 2. If Android I need to be able to install whatever I want from APK or from SAI, and not be restricted by existing modified versions of fbreader or similiar which prevent me from installing a package of the same name, or if it normally won't, then rootable so I can anyway. If Linux, I'll figure something out.
Screensize likely won't be an issue from what I've seen.