Can Linux save the UMPC from extinction?

Some devices set the world on fire, just ask Apple for details. Others, do not. The UMPC seems to be falling into the luke warm gadget category at the moment, and despite the best efforts of the usual suspects sales of the Ultra Mobile PC remain disappointing. Maybe because nobody knows what the UMPC actually is. Is it the Microsoft/Intel defined, Windows Tablet PC powered device with a touchscreen of less than 7" in size? Is it one of those bizarre Nokia Internet tablet things which have made such an impact that I am struggling to recall the name, N800 is the one I think? Or maybe it is because nobody knows what to use it for. Larger than a smartphone but smaller than a sub-notebook is a strange territory to be in, and no killer application springs to mind.