In each configuration in which the Display applet alerted me that the "Virtual" line needed to be added to xorg.conf I was left with the blank screen I mentioned.
In each configuration in which the "Virtual" line was *NOT* needed I could successfully setup two different monitors without mirroring. For example now I have a working 1024x768 on both monitors and I had 800x600 on both working previously.
I tried a few other resolution configurations.
In each configuration in which the Display applet alerted me that the "Virtual" line needed to be added to xorg.conf I was left with the blank screen I mentioned.
In each configuration in which the "Virtual" line was *NOT* needed I could successfully setup two different monitors without mirroring. For example now I have a working 1024x768 on both monitors and I had 800x600 on both working previously.