The 15" won't be as thin as its smaller counterparts. It will still be a pro level machine, as an internal redesign with total removal of the optical bay, will yield a similarly functional machine as we have now, but thinner and lighter.
I think they'll still be able to use the upcoming M-series standard voltage Ivy Bridge processors in the 15 and 17" models, with U-series low voltage remaining in the 11 and 13" models. Still a distinction in both size and power among the line, but with a unified design, and the benefits of the smaller form factor for 15 and 17" users. (I just got a 15" the other day and might I say its freaking huge)
However, its entirely questionable if they'll still have discrete GPUs. I think perhaps not.
They'll have a thicker hinge than the 13" MBA, so it will likely be able to retain an extra USB port and SD card slot, but say goodbye to Ethernet and FireWire. Granted, you don't need either port. You can soon buy small Thunderbolt hubs for your desk that your Ethernet and FireWire devices connect to, all going into 1 Thunderbolt port. That's
better than the current implementation of multiple ports. So a design and functional victory here.
The real question is storage capacities of the SSDs and RAM, and the prices. Enter Anobit, hopefully.
If the Anobit purchase can leverage costs of the soldered internal SSD, then perhaps a 256 GB will be the low end, with 512 & 1 TB options, at modest price hikes for each. Then there is RAM. Apple currently charges $200 for 8 GB of RAM....a $150 overcharge, and why most people buy aftermarket. Not an option on MacBook Airs. Furthermore, Apple doesn't offer a 16 GB option for these machines, which they of course support.....but this could change.
I guess it could look like this...
15" MacBook (Air/Pro)
$1799
2880x1800 Retina Display
2.6GHz Quad-Core i7-3720QM
4 GB DDR3 (8 GB BTO option - $100)
256 GB SSD
Intel HD 4000 Graphics
2x USB 3.0
1x Thunderbolt
1x SD Card Slot
802.11ac Gigabit WiFi
Impossibly Thin
3.9 lb
&
15" MacBook (Air/Pro)
$2,199
2880x1800 Retina Display
2.7GHz Quad-Core i7-3820QM
4 GB DDR3 (8 GB BTO option - $100)
512 GB SSD
Intel HD 4000 Graphics
2x USB 3.0
1x Thunderbolt
1x SD Card Slot
802.11ac Gigabit WiFi
Impossibly Thin
3.9 lb
&
17" MacBook (Air/Pro)
$2,499
3840x2400 Retina Display
2.9GHz Quad Core i7-3920XM
4 GB DDR3 (8 GB BTO option - $100)
512 GB SSD
Intel HD 4000 Graphics
2x USB 3.0
1x Thunderbolt
1x SD Card Slot
802.11ac Gigabit WiFi
Impossibly Thin
5.1 lb
*Note, the BTO RAM prices and SSDs are considerably cheaper than what Apple offers today, but I believe if a full redesign and shift to MacBook Air speed/simplicity is to occur, Apple would need to make the new NON-upgradable MacBook Pros more attractive at purchase. Especially with the likely abandonment of discrete graphics. Something's gotta give. I'm thinking the Anobit purchase will have a lot to do with offering higher capacity SSDs in these Pros, while maintaing price points.
So, would you buy one? Given those specs?