Only times I've had issues removing/upgrading fglrx in the past 3 years and a half I've been using it is when openSUSE still had saX (or was it Sax... SaX... yeah whatever...).
Since it kicked the bucket, I've had to shut down X before running the installation script. That's it.
Never used any additional repository nor extra script.
Code:
# cd /usr/share/ati
# ./fglrx-uninstall.sh (now ./amd-uninstall.sh)
*reboot*
Ctrl-Alt-F1, log in
# init 3
# cd /wherever/I/saved/the/binary/
# sh ati-[Tab]
[Yes] [Yes] [Yes] [Ok] yada yada...
# rm /etc/ati/amdpcsdb
*reboot*
...
Profit!
I suggest people having issues with fglrx rethink their troubleshooting workflow.