How about a plugin to support the input and conversion of eTextbooks formated in the
Wolfram (Mathematica) "Computable Document Format (.cdf). The construction of the
files looks, to me, like an XML/HTML based construct and Calibre seems to work well
with such ebook/document formats.
A look to the subject through the free eTextbook site, http://www.ck12.org
a start to see if it is practical to create a plugin for it.
This is in hopes that Ectaco's new Color jetBook can handle it, at some point.