Xorg, USB, and disappearing keyboards

Hello list,

I'm having a rather irritating problem with my Thinkpad X60 and Xorg.
Previously, I have been able to plug and unplug an external USB keyboard
with impunity. As of a few months ago, when I unplug the external
keyboard, the built-in one stops working. If I plug the external one
back in, both keyboards work again. 

I worked around this for a while by switching to the console and then
back, which seemed to poke hald or whatever to get things working again.
A week or two ago, this workaround stopped working -- when I switch back
to X, I just get a blank screen. That's a bug of some kind too, but a
nebulous one, so I'm focusing on the one that's more debuggable.

Looking at the Xorg.0.log, I see this on unplug:

(II) config/hal: removing device Apple Keyboard
(II) UnloadModule: "kbd"

Thanks HAL, but I still need that module. I tried adding a separate
InputDevice entry, so that X might retain the driver, but the behavior
is the same. Could anyone point me in the right direction?

Here is the log and config.

http://redundancy.redundancy.org/Xorg.0.log
http://redundancy.redundancy.org/xorg.conf

Thanks,
David