When an emerge depends on several packages it would optimize time if the packages were fetched while compiling the packages already fetched. So: emerge openoffice should run: emerge -f openoffice & emerge openoffice
Nick has an implementation of this. Dunno the status of it, let him tell you :)
I'm working on it... Does the things you are asking about, plus a great deal more. Bug reports and Functionality requests are welcome. (Post them here.) --emptytree DOES NOT play well with my code. It updates portage, and causes mis-matched code... I should have this remedied in the near-future. Current code can be found at: http://gentoo.twobit.net/scripts/portage/threaded/ ALWAYS emerge the version of portage that matches the version of my code first. i.e.: portage.py-2.0.9-nj and emerge-2.0.9-nj emerge \=portage-2.0.9 THEN follow the directions.
*** This bug has been marked as a duplicate of 1661 ***