I don't think it would be a good idea to keep such a large set of books on a card anyway because of the time to index them all. I'm curious why it's so important to have the big storage. Are you trying to keep a whole Gutenberg or Blackmask DVD on it or something?
Most of us seem to have more internal storage than we need for books anyway. The SD card is useful to me just because it allows me to move books around without the Connect software.