Is there an android distribution that presents a stripped-down ereader interface and nothing more? The reason for this is just a matter of ultimate usability.
Android is just a platform like OS that anyone can add toppings (apps) to.
If you want a really clean minimal OS good for E-reading then install Titanium Backup or Root Uninstaller, and just uninstall all of it (including default Homescreen) and just leave your favorite E-reading app (Kindle, Aldiko, Cool Reader, whatever). This way you will have a dedicated E-book reader like device without resorting to flashing a new ROM.