There are some threads around here about Xorg and HAL (or not-HAL) and I believe at least one of them outlines building X for Slackware without HAL. Right off, I cannot recall the details. Search around a bit and see what you find.
Meanwhile, if you just want to toss HAL out of your devices situation, consider the following for your xorg.conf's "ServerFlags" section:
# try one or the other: Xinerama or randr
# as software + drivers improve
Option "Xinerama" "True"
# Next 3 lines: disable HAL input hotplugging:
Option "AutoAddDevices" "False"
Option "AutoEnableDevices" "False"
Option "AllowEmptyInput" "False"
# Which of the next 2 lines is right? Either of them?
# Option "RandR" "True"
# Option "RandRRotation" "True"
Those 3 bold lines may well solve your problem, at least for now..
UPDATE -- coincidentally, I just came across this thread you might like: