Just to avoid suprise build failures for you: I did some changes to the project config that will affect many builds, but at least no package in factory should fail due to this as I prepared this in several staging projects and also submitted fixes early:
1. We switched from libpng14 to libpng15 default, Petr submitted patches to many packages already and we think we're ready for it.
2. I removed 4 packages from default install in build environment: sysvinit-tools netcfg login udev