Microsoft has released a(n) UMPC Display Emulator.
http://msdn.microsoft.com/mobility/tabletpc/umpc/umpcbeta/default.aspx
"The UMPC Display Emulator Beta application enables you to test your application's layout and screen behavior as it appears on an ultra-mobile PC (UMPC). Use the UMPC Display Emulator to confirm that your program is legible, accessible, and provides a great user experience when running on an ultra-mobile PC."
If you have a TabletPC, as I do, you can get even more of the UMPC experience, albeit with a much larger device. But still.. pretty cool.

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