New Retina MBP, user upgradeable SSD drive?

At this time, no. The SSD does appear to be removeable though. I'm sure Apple Stores will sell or upgrade it for you soon. Also, third party companies may come out with a replacement in the future. Expect higher prices thantypical SSD's for these options though.

Correct. You have to wait for Apple or someone else to develop a SSD that will fit.

Because it has to fit into the space for it.

yep, they're proprietary to the new MBP's.

judging by pictures and the internet and verbiage from Apple itself these are NOT replacable.

along with the MacBook AIR the retina MBP is "Flash Storage",

NOT "HDD" or "SDD" like the non-retina MBP is.

http://www.apple.com/macbook-pro/specs/13-and-15-inch/ specifically states "rpm hard drive" or "solid state drive"

http://www.apple.com/macbook-pro/specs/ specifically states "flash storage" along with how the AIR is defined. and ive never read anywhere about being able to replace the flash storage on an AIR.

This goes along with the slight vagueness of memory on the different MBP's as well..

the AIR and retina-MBP specifically state 'onboard memory' and thus are not replacable/upgradable.

the non-retina-MBP states 'memory' and are replacable/upgradable.