To answer your question directly: I don't think there is. Technically it's certainly possible to render any TrueType/OpenType font at whatever size you want, but the size is determined by the software configuration not the font itself.
Originally Posted by delphidb96
Maybe someone can start up a line of freeware fonts optimized for the Cybook
That's a good idea. I think, I might do just that in the next few days ... maybe.