An iPhone/iPod-Touch is not a netbook, by any stretch. They are, at most, a low-end (in terms of size/display) MID. A netbook is a very particular category within the MID/UMPC arena. But even if we aren't pedantic about "netbook" and we focus on whether or not an iPhone/Touch fills the role of a netbook ... you're still completely wrong.
The netbook fills a very particular niche between a laptop and a pocketable. Laptops are too big, and pocketables are too small, for this niche. While you say that a netbook isn't any more portable than a laptop, the fact is that there are lots of gadget bags that are big enough for a netbook but not a laptop. Or even bags that are otherwise big enough for laptops, but that now have more room for things like books and other gadgets once you're not using most of their space on a laptop.
While you say "can't do much besides internet and email", you say it like it's a bad thing. That's exactly what they're designed for. Unlike an over-priced, over-powered, laptop, a netbook isn't designed to be a full power desktop replacement. It's intended for the lighter workloads, the common tasks we ALL do (students, professionals, casual users, retirees, etc.), not the heavy lifting that only people in specific markets need.
So far, you're right that the iPod Touch and iPhone are in the same mold. Everything I've said to differentiate a netbook form a laptop holds equally for the Apple MIDs. But ... have you ever tried to take notes for a 2 hour meeting on a pocketable device? I have. In my case, I've done it with both a Nokia N800 and a Nokia N810. What I found, over time, was that the small size kept it from being a useful replacement. The N800 had the same problem that the Apple devices have: you can't interact with a full screen application AND type at the same time.
The N810 improves this with a physical keyboard, but trying to type full speed with your thumbs is just not a sustainable plan. Thumb typing is great for VERY short things: TXT messages, 1-3 line to-do items and notes ... and that's about it. Anything more than that, and you're going to be lagging behind the events going on around you. For meeting notes, that becomes a distraction and a liability to the task at hand.
I also found that the small screen (which is bigger, and has better resolution, than the Apple devices) was ok for some things, but really just plain too tiny for other things. Again, note taking comes to mind, where I wanted just a little more screen real estate for looking back over my notes. On a 4.1" screen, there was just not enough room to display all of the information I wanted to view.
A 7" or 9" screen is a HUGE improvement in this regard. Easier to read, able to display more information, able to give you a "bigger picture" (I mean that in the "awareness" sense, not the "big JPEGs" sense). The Apple devices, frankly, can't compete here. To give a "big picture", you lose the details. To show you the details, you lose the "big picture". While a 7" screen isn't going to be as useful as a 22" screen, in this regard, it is, in my experience, "good enough" for the light tasks a netbook or UMPC is intended to cover.
And then there's the keyboard. Sure, MOST netbooks use cramped keyboards, but people seem to adapt to them enough to type as decent speeds. And then there's the wide-screen netbooks, like the Sony Viao P and the HP mini 1000. Imagine the current metal Apple Bluetooth Keyboard, with a matching sized display attached to it. You can type full speed, and you've got a decent (not great, but decent) screen for viewing what you're typing (interestingly, this is very close to one of the mock-ups).
Personally, I'd LOVE to have a convertible tablet (swivel screen) format Mac with a 8.9"/9" screen. I think that would be amazingly great. But I also doubt that you could make it happen with aesthetics that would live up to Apple's standards. As much as I think the HP mini 1000 with Mac OS X would be a sexy beast, I doubt that it'd be "different" enough for Apple, and I don't see that being a form factor that works with a touch screen. That's why I think the most likely case something more like the Samsung Q1 series (without the physical thumb keyboards).
I'm thinking either something like the "Touch Book" (tablet with optional detachable/clip-on keyboard), or something like the Q1 (pre-Ultra) that relied upon virtual thumb keyboards or a completely separate standard, but small, keyboard (USB or bluetooth).
Imagine an iPod Touch with a 9" or 10" screen, running real Mac OS X (but with an alternate Finder view that looks like the iPhone, and the ability to run iPhone and iPhone-like apps), that has not only the portrait and landscape keyboards (only the landscape keyboard would be finger size, like one of the mock-ups, instead of thumb size), but also translucent split thumb keyboards that can be used in landscape mode. Also, with a screen this big, a portrait thumb keyboard still gives you a usable amount of screen real estate for viewing the app you're working with. Then imagine a docking port on one of the _long_ edges (not one of the short edges), that can be hooked into a docking station for use with a real keyboard ... or that can be clipped into a clamshell case that gives it a more standard netbook form factor (that would only be bought by people who wont mind a slight "ugly factor").
So ... while an iPod Touch definitely qualifies as a MID, it definitely doesn't qualify as a netbook. And, a netbook definitely fills a role (in use, and size) that puts it in a "useful, but lighter than a laptop" niche, while still being more capable than a pocketable device.
And I, for one, welcome the idea of Apple entering this market. Linux has come a long way in the last 8 years, but even Ubuntu and Maemo are still no OS X.
