As of now, jadetex doesn't emerge if texlive is the tex-dist installed. To fix this very simply, in the ebuild, there is a function: has_tetex_3 just change the first line of this function to include has_version '>=app-text/texlive-2005' to fix.
On a similar note can we please add the texlive ebuild that's floating around in a bug report to the tree? It compiles fine and runs fine. The one in portage right now straight up doesn't work.
This is fixed in jadetex-3.13-r1, but there is no new revision since texlive isn't officially supported yet. As for the texlive ebuild, I believe that Martin Ehmsen is working on it but our priority for the time being is to stabilize tetex-3 (which should happen very soon). Since a TeX distribution is pretty heavy and complex, we'd better test it a lot before adding anything, even hard masked.