I wrote this patch to mediawiki-1.4.5 (works for 1.4.6 too) that integrates wikipdf into mediawiki. See bug 2852 http://bugzilla.wikipedia.org/show_bug.cgi?id=2852
It seems to fix the Commons Images problem since it doesn´t download the images anymore (wikipdf code is now a mediawiki feature running on the same server).
Felipe Sanches
PS: Brion noticed that this patch is buggy because shell commands are not sanitized, I´ll try to fix these problems.