tetex and the current texlive ebuilds use texlinks for creating symlinks from
formats to engines, like latex -> pdftex in /usr/bin for texlive.
The problem of handling files via texlinks is that those files are not under
the control of portage, thus unmerging tetex or texlive leaves the symlinks
around, pointing to nothing.
I'm almost finished writing/importing the functions of texlinks in the eclass
and creating the symlinks there, so that they will be in CONTENTS.
The drawback of doing this is that if somebody had a previously installed
version, that will cause collisions with those files that are on the system and
don't belong to any package.
As migrating to texlive will be a big step, I think it's the right time to fix
that.