Is it possible to use a Google TV device without a TV connection? With the price of the Logitech Revue having dropped, I am interested in using the Google TV device purely for the (internet) functionality of the Android platform. 

Since a "Cable or Satellite set top box with HDMI out" is listed as a requirement I am wondering if the device can be used without the HDMI input being connected.

I am aware that this might remove the TV functions that are at the core of the device.
Yes, you will be able to use the Logitech Revue Google TV unit without the Set-Top Box.  I am doing this with the Sony BlueRay Player w/GTV.  During the set-up process simply skip the section for setting up the TV provider and you should be all set.

Here is a youtube video of a Revue functioning without a cable or satellite STB.