Hi DDarcy
I don't have a solution for you, but I know that this has been seen and reported before.
The explanation we got back from the beta team was that this is behavior that has been reported when using some graphic card drivers on certain systems. They also stated that this behavior will be resolved as these drivers are optimized for Windows 7 with future updates.
I have a similar problem with an ATI X600 card running dual monitors. The second monitor experiences the flicker, but it only appears for a few minutes at start up and then stabilizes until the next startup.
Hope this helps.
Thank You for testing Windows 7
Ronnie Vernon MVP