Aline used an forked udev script from the gentoo community and provides more info how to remove systemd from your Arch installation without problems.
I'm quoting Aline now, whom I thank again for her contribution:
This is my PKGBUILD from the udev fork: http://pastebin.com/L5ZTkBVCCustomize-pkg you can download here:
And this is the old PKGBUILD from initscripts: http://pastebin.com/LAjxTpEZ
I've installed both, rebooted. There are a lot of packages that is linked against udev libraries, so I had to rebuild all of then. For this I use yaourt + customizepkg-new from aur. For most of the packages I only had to create a empty file in /etc/customizepkg.d/. For example xorg-server, I have a empty file /etc/customizepkg.d/xorg-server
For more details see also: http://bbs.archbang.org/viewtopic.php?pid=18037#p18037
Other relevant links about alternative solutions:
about udev-lts from Jubei: https://bbs.archlinux.org/viewtopic.php?id=148429
about Ignite, asimple and robust init replacement
Allow disabling the build of all of systemd, leaving just udev: http://www.spinics.net/lists/hotplug/msg05503.html
We have to wait and see what will surface as the most easy, reliable and lasting solution.