Stephen Montgomery-Smith posted some patches for bsd.port.mk to the ports mailinglist to speed up the package dependency list creation. He did cut down the time from about 2min30sec (package dependency list of gnome2, tested on my system) to about 15 – 18sec. I enhanced this and now the time is down to about 12sec and a lot less programs to execute in the call (may be important on slow systems).
The patch for bsd.port.mk in my ports-patches directory contains more than only those improvements, the other part is not subject to submission yet.
If nobody finds some problems with the patch I will send it to GNATS and assign it to portmgr for inclusion into one of the next experimental ports builds.