Same thing here, I just installed Wheezy AMD-64 on brand new hardware. Use ATI Radeon driver xserver-xorg-video-radeon.
Keyboard and mouse are non-functional. Can't CTRL-ALT-F1, neither ALT-SYSREQ
I can SSH into the box, can't see anything strange. According to /var/log/Xorg.0.log the config files from /usr/share/X11/xorg.conf.d
I can find one file with something about a keyboard:10-evdev.conf
Identifier "evdev keyboard catchall"
But it doesn't say a thing to me, either good or bad.
There is no message in Xorg.0.log about a missing or disabled keyboard.
Edit: removing /run was not a good idea, the machine wouldn't boot after that. I thought it was a symlink to /var/run? Anyway, recreated /var/run and ln -s /var/run /run and booting is fine again.