Many readers note that Apple was granted a US patent on "the ornamental design for an electronic device, substantially as shown and described". The US patent was filed on March 17th 2004 and posted today (May 10th, 2005).
Readers will recall that many of the same images were revealed in August 2004 (images).
The patent application images this time also depicts a person using the device as a tablet with touch screen. Little other information is offered on this potential design.
Of interest, this is not the first time Apple has worked on a tablet based computer. An early prototype Newton is pictured here (Messageslate) as well as a tablet-based PowerBook prototype is pictured here.