Make a piece of paper the size of the device with a 9.7 inch screen, hold it in your hands and then ask yourself, "would Apple really sell something like this with full Mac OS X on it?"
I've done it and frankly, it just doesn't make sense why they'd do that.
Like the "problems" that are constantly being had on all other computers that Apple sells?
As far as Apple's concerned, EVERYTHING can pass through the App Store and they'll take a nice 30% chunk off those sales. Sounds like a pretty sweet deal to me!
Some reasons why this tablet won't have OS X:
Apple makes too much money from the AppStore, OS X would let you install whatever you want from wherever you want.
I have. I use a graphics tablet instead of a Mouse for 95% of my work.
1. Inkwell is useless.
2. Inkwell has nothing to do with multi-touch. It requires a stylus.
And while there have been many tablet computers with styluses. They all had one thing in common.
They were commercial flops.
Trying to shoehorn a full desktop application into hand-held or a small format machine produces an unsatisfactory experience. This is why the Origami project failed.
My prediction is: iPhone OS and iPhone OS apps with additional features and enhancements to take advantage of the larger display and higher specifications.
I don't think it will be "just" a larger iPod touch (for reasons already explained) and I don't think it will use Mac OS X (for reasons already explained).