Retina 15" Matte Macbook Pro with next-gen i7 and 512gig SSD and 16gig RAM in Air-like form factor.
512GB SSD - I doubt they'd offer that.
More likely to be 128 and 256GB configs...
I could live with 256 myself (just).
480 would be good but would make the end price horrendous.
Essentially a 'Retina Display" would allow us to order a stock MPB without having to specify the optional 'hi-res' display which would be nice.
....so I'd say the "Retina Display" 15" would be something like this
(realistically):
15" MacBook Air-like form factor
DualCore i7 2.2
128GB SSD
Retina Display
512MB Video (possibly with some extra as part of some on chip thingy)
4GB RAM
USB/Thunderbolt I/O
No optical drive
A killer version (sold as a stock machine) would be more like:
15" MacBook Air-like form factor
QuadCore i7 2.4+
480GB SSD
Retina Display
1GB+ dedicated video
8GB RAM
USB/Thunderbolt/Firewire I/O
No optical drive
Ok so you'd want to be able to expand it to 16GB RAM of course.
Having all this stuff in a thin form factor is a hard task - heat/size etc.
But hey its Apple, and even the fact Mr Cook dismisses A5 chips in laptops you never know. Having something that competes with a mobile Intel Quad Core i7 and runs all apps, OSX etc... who knows