Is the HDMI output on the Xoom (or indeed any of the newer tablet devices) capable of displaying different imagery to that being shown on the device's screen? Is it limited to cloning? Can the internal screen be blanked (e.g. if watching a movie on a bigger screen).
I've seen examples of iPad games that display a secondary screen on the device itself when outputting to a TV (e.g. racing games showing the map on the device which is doubling up as the wheel).