Tablet device... Why bother?

For years, there have been rumors of a mythical tablet, or "tablet-like" device from Apple. I hate to spoil everyone's fun, but the tablet device is already out there, and it's called the iPhone.

Yet many people think any day now, we'll see a device with perhaps a 7" screen that would pack the power of laptop, or in some speculation, the device would act as a companion device to a house of Macs. What good would this device be? If you want to sure from the couch, and find a laptop too bulky, there's already the iPhone and iPod Touch. If you're looking for a lightweight design, that comes along with its own drawbacks, there's the Macbook Air. A 7-inch screen isn't large enough to do much more than surf the web. For full computer capability, you would need a physical keyboard, and that of course means a bigger device or a smaller screen.

Maybe I'm missing something here, but I just don't see a place for this in the product lineups. If you want to talk about product gaps, we can talk about the gaping hole where a low-end tower should be, but as for portable devices, the choices are already there.