The modular X CVS HEAD sources fixed the freezes with my ATI card. Build instructions are here.

Update: I got my german keyboard working again through the following steps. I am pretty sure that some of them are redundant.

Creating some links (xorg is installed beneath /opt/xorg-cvs):

$ cd /etc/X11
$ ln -s /opt/xorg-cvs/share/X11/xkb .
$ cd /usr
$ ln -s /opt/xorg-cvs X11R6
$ cd /usr/X11R6/lib/X11
$ ln -s /opt/xorg-cvs/share/X11/xkb .

Editing /etc/X11/xorg.cfg

...
Section "InputDevice"
Identifier "Generic Keyboard"

Option "CoreKeyboard"

Driver "kbd"
Option "XkbRules" "xorg"
Option "XkbKeycodes" "xfree86"
Option "XkbTypes" "default"
Option "XkbCompat" "default"
Option "XkbSymbols" "de(pc105)"
Option "XkbGeometry" "pc(pc105)"
EndSection
...

And running this:

setxkbmap -model pc105 -layout de -variant nodeadkeys