Whatever you want to call them, would a smartphone with around a 5.5" to 6.0" touchscreen be the perfect connectivity device?
For reference; The new Galaxy Note, with its 5.3" screen, is about the size of a checkbook, but an inch shorter in length. A 3"x5" card would be a 5.8" screen. The Galaxy Nexus has a smaller 4.65", HTC Titan a 4.7" and Dell had a 5" Streak phonblet, but killed it. These compare to most smartphones that have 3.2" to 4.3" screens.
Galaxy Nexus 4.65" & Galaxy Note 5.3"
Galaxy Note 5.3" & Galaxy Tab 7.0"
A while back there was a tablet thread and since then, a lot of tech reviews I've read have praised the 7"er tablets for being the most useful and portable in their line of work while outselling the plethora of 10" offerings. In that thread I made the case that 7" tablets were too small for the full web and video experience, 10"ers are cumbersome, so the 'perfect size' is a 8" to 8.5" that could fit in suits, cargo pants and purses. A few 8" to 9" tablets - Galaxy Tab 8.9", LG Optimus 8.9", Archos 8.0" G9 and the new Motorola XYBoard 8.2" and Pantech Element 8.0" - are available.
But all these tablets have a problem - they're not phones and they're not small. Apps have been developed to sync your tablet to your phone, allowing one data plan, but you still need the phone to make calls. Even if a tablet had a phone plan and bluetooth headset, lugging the smallest 7" tablets around just to make calls is a little dumb.
So, would a 5.5" to 6.0" phonblet capable of making calls be large enough for the web and media experience without becoming too large to be discretely transportable? Could it be the one connectivity device to replace your phone and your tablet, as well as your car's GPS or your video camera?