Oh I almost forgot -- how bout a Sega Pico (out of production -- check E-Bay). My niece had one of those. It's "Edutainment" or "Entucation" or "FunaMcLearning" or something like that.
It was this cartridge based thing with a pen and the cartridges were actually books. It may seem kinda lame for the older set -- but it still had better software than the Sega CD.