A 'new Newton' doesn't even make sense.
The only thing the touch/iphone lack, compared to a newton, is apps.
You don't need a different form factor for that - you need a change of philosophy. And that is one change I do not see coming down the pipeline.

If they were going to make a proper platform, they'd be better off with a subnotebook-sized multi-touch tablet running full OS X. At least that wouldn't cause as much confusion in their device topology. Lord knows they already have one head-scratcher in the form of the iPod touch. (I still have no idea who that thing is supposed to be for)