A nice enhancement would be to be able to get percentage/progress-bar instead of the regular make-output. This would also make it possible to make a usable GUI-frontend to portage. The idea has already been realized by procmake (http://software.zuavra.net/procmake/), but simply setting MAKE=procmake doesn't work with portage. Would this be a feature to include in future versions of portage?
echo "alias make=procmake" >> /etc/portage/bashrc should do it. Meanwhile, not a massive priority (and curious about people's take on it screwing with builds)...
also... dependant on a procmake ebuild in the tree, which should be opened as a seperate bug (preferably) with an ebuild attached :)
Consider this closed as CANTFIX. There is no reliable way for portage to gather this data.