To answer your question about form factor, no, the Retina MacBook Pro does not use a standard 2.5" profile. It is a proprietary Apple design that will probably take 3rd parties a while to copy.
This is unrelated to your question, but why do you want/need so much flash storage? The maximum configurable 512 GB should be good for anything you need on the go, and you can always use a 1 TB or larger external HDD at home.