I had a problem with some sourceforge mirrors timing out.

looking at /usr/portage/profiles/thirdpartymirrors

idsoftware ftp://ftp.idsoftware.com/idstuff ftp://dl.xs4all.nl/pub/mirror/idsoftware/idstuff ftp://ftp.fu-berlin.de/pc/g$

jpackage ftp://mirrors.dotsrc.org/jpackage ftp://jpackage.hmdc.harvard.edu/JPackage http://sunsite.informatik.rwth-aac$

kde http://ibiblio.org/pub/mirrors/kde ftp://ftp.kde.org/pub/kde ftp://ftp.gtlib.cc.gatech.edu/pub/kde ftp://down$

kernel http://www.kernel.org/pub http://www.us.kernel.org/pub http://www.de.kernel.org/pub http://www.fr.kernel.org/$

liflg http://liflg.death-row.org/files/native http://mirrors.ecology.uni-kiel.de/games/liflg/native http://home.coc$

lokigames http://mirrors.dotsrc.org/lokigames/updates http://lokifiles.tuxgames.com/updates

macromedia http://sluglug.ucsc.edu/macromedia http://ruslug.rutgers.edu/macromedia http://macromedia.mplug.org http://ma$

nero http://ftp3.use.nero.com/software/NeroLINUX http://ftp4.use.nero.com/software/NeroLINUX http://ftp5.use.nero.$

mplayer http://www1.mplayerhq.hu/MPlayer http://www2.mplayerhq.hu/MPlayer

mysql http://mysql.mirror.secondchapter.info http://mysql.secsup.org ftp://mirror.mcs.anl.gov/pub/mysql http://mirr$

Theres a snippet

I just dumped the lagging mirror from the file and now i dont have to wait for the server to timeout before it jumps to the next