Great way to look at it. Unfortunately those that use those applications [photoshop, maya, zbrush, illustrator, etc.] long hours while sitting at a desk, have the extensive amount of RAM (Protected even), HDD space needed, and a stable Ethernet on LAN connection via a Mac Pro. Consider picking up even the mid-tier Mac Pro + a 21" Cintiq and you get the equal or close after tax price of the ModBookPro that is available immediately.
Furthermore their work - usually for a large company or a solid business - wouldn't allow them to take home their work OR its smarter to leave their work on a desktop (secured by Kensington, motion-detectors, and central alarm security). Even more so they can work on their projects over a VPN/RSA connection to the offices remote servers on their personal/work MacBookPro's.
Ah, not everything with Pro in the title appeals to "large companies and solid businesses" - what about us starter-uppers? For me, the benefits/convenience of the converged products validate (somewhat) the purchase price.
I've done the Mac Pro/Cintiq setup already - it almost
demands two displays, well with the Cintiq 12wx at least - a 12" 1280x800 is insufficient there. Sure you could get a Mac Pro + 21" Cintiq, but I'm sure people interested in the ModBook pro have weighed that option up already. I have. Didn't suit my budget at the time, and as I realised, I move about too much even for the Cintiq 12wx to be convenient. Next time around I won't cut corners, I'll get a souped-up modbook pro.
A 15.4" 1440x900 display as standard? And fully portable? For me, that's better. What, do you
only do work at the workplace?
Even a 12wx, small as it is, is far from convenient for setup in multiple locations should you travel a little, and don't even bother on a plane or train. Sure the overall size of the device is fine, but it requires constant tethering to both a computer via USB and video port, through a transformer box, plus power. ModBook Pro is the evolution.
Either way, its still cheaper to by a MBP+21" Cintiq to get the same thing.
If you think it's the "same thing" you're not. The. Target!
...whats its battery life? And its weight? I'll bet you'll need a knapsack to hall that to & from destinations
Can't imagine additional battery drain being much more than it would be to plug a USB-powered Intuos into a notebook. There's nothing other than the tablet functionality present that should take up any more energy than is usual with a MacBook Pro. (GPS?) It's 0.93 inches thin and 6.6 pounds, so friendlier dimensions than a 17" MacBook Pro from what I can tell.