According to the Impatica employee with whom I've corresponded, they will provide complete corresponding source upon request via postal mail (and payment for media cost). I have not yet mailed my request, but I will be doing so.
Please, don't go all Slashdot-stupid on Impatica. I've held off posting information on the ShowMate before now because I don't want them attacked. I'm hoping with some polite encouragement, they'll fully comply with the GPL. Email threats and insults will not help matters.