I hereby invite all my dear friends here over to the Alphasmart reddit thread where some brave souls are designing a replacement for the Alphasmart - something smaller, lighter, cheap and able to use any USB keyboard:
https://www.reddit.com/r/AlphaSmart/...hing_keyboard/
p.s. the Nook NST could do it. Mine's rubber disintegrated after a few years though and then wouldn't switch on. Plugging in a USB keyboard via the weak USB plug was sketchy anyway.