Why not check into bug 1661
(http://forums.gentoo.org/viewtopic.php?t=1661)?

Carpaski had a set of patches at
http://gentoo.twobit.net/portage/threaded/ against .36- isolating the
emerge changes shouldn't be too much, although portage.py might take a
bit more.  At the very least seems like a better approach to a permenant
solution, although the age of the code might warrant just rewriting it
from scratch.  Portage.py's modifications would at the very least
require updating for .49+ global var adjustments...

/me heads to bed.
~brian