Funny that the L in ldap stands for lightweight, and yet clearly there is interest in a lightweight version of what has become a somewhat bloated protocol.
We'd love to offer something like that, but there's all kind of considerations around liability with repairs. Plus we're entirely run by volunteers, and watch repairs take a lot of time.
That being said, a store for refurbed Pebbles might be doable, but it would be a big time and cost overhead.
I have a Onyx Boox Note Air, and it's amazing for reading / writing. I have an SSH app on it (it's Android) and the experience starts to fall apart there. I can type significantly faster than it can refresh and render the characters.
That being said I'm sure there's some magic you could do to reduce latency here if you tried. I know it does some magic behind the scenes with the drawing to improve responsiveness.