Hooray, I had success building calibre-0.4.137-1.x86_64.rpm and its src.rpm for Fedora 10, using the system odfpy, pyPdf, and python-{cherrypy,cssutils} packages.
I wound up deleting the bits about the postinstall, as I wasn't in the mood to solve that one (possibly don't execute that section if RPM_BUILD_ROOT is defined, but I don't know, nor do I feel like messing with exceptions from os.environ for a simple unset envvar. I did mention I dislike coding in python...
)
I also made good use of the packaging info here, as I tend not to package python much:
http://fedoraproject.org/wiki/Packaging/Python