Ok, it kinda works a little.
I got commit rights in the mercurial repo, so now you can get the very very alpha version here.
This triggered several bugs in rst2pdf, so you need SVN rst2pdf for it to work.
Plain restructured text ... with some caveats (example: footnotes are semi-broken)
Index generation (not 100%, but maybe 75%)
I don't know what other pieces of sphinx require specific rst2pdf support, but I will be hitting them as they come.