Dual Monitors Breaks 3D Desktop Effects (Compiz)

When I left home last night, I had full functional working 3D desktop effects. Once I added my two 1600x1200 monitors this morning and resized my virtual desktop size past the breaking limit, that all went bye-bye. :( I vaguely remember reading that increasing the desktop size on my video card will automatically disable this wonderful feature. Surprise. It did.

Well, at least with the old video driver, it's still smoother than the newer ones. Bummer though. I was really liking all the extra "new OS" bells and whistles. Maybe I can find a work-around someday, but I highly doubt it.

EDIT:
Here's the URL that discusses the root of the problem (I think it still applies to 8.10, but I'm not certain just yet... will look further):
http://ubuntuforums.org/showthread.php?t=580891

And some more specific to the Dell Latitude D430:
http://www.winchen.de/PHPWIKI/doku.php/public/delld430

Workaround:
Switch xorg.conf on bootup depending on whether or not external monitors are attached.

I don't use Compiz or most of Ubuntu when I'm at work anyway, so why worry about it? However, when I'm just using the laptop, perhaps just running a virtual desktop of default size is fine? That should allow compiz and other 3D stuff to run splendidly.

Getting started:
Install "xresprobe"
Create two xorg.conf files; one with the 3200x1200 virtual desktop, one with the default (2048x2048)
Create shell script that runs during startup to use one or the other xorg files.
Create a symbolic link to run the shell script just before x11 runs.

I got the basic idea from here:
http://sernaonubuntu.wikidot.com/multiple-monitors

Also, a great site about configuring XRandR and XORG to be happier together:
http://www.thinkwiki.org/wiki/Xorg_RandR_1.2

Results of Workaround:
It worked! I don't have Compiz running when I'm using my dual monitor setup, but I do have it when I'm just using the laptop by itself. I didn't end up using all the fancy stuff in the above post. My xorg.conf files are pretty simple (subsitute the virtual size in each for your preferred sizes):

# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# Note that some configuration settings that could be done previously
# in this file, now are automatically configured by the server and settings
# here are ignored.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "Monitor"
Identifier "Configured Monitor"
EndSection

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
SubSection "Display"
Virtual 3200 1200
EndSubSection
EndSection

Section "Device"
Identifier "Configured Video Device"
EndSection