Re: ETA for nV GeForce GTX 675M w/2GB
It's impossible to say without first-hand experience, unfortunately. Optimus is pretty well-supported on Windows, but as you pointed out the situation on Linux is a bit messy right now.
If I had to guess, they used the same design with a different chip and display won't be wired either, but it's really impossible to know unless they document this somewhere.
Are there other options in the SBIOS pertaining to selecting the VGA device, and have you tried all combinations there? I know on recent Dell laptops you can totally disable the Intel device and directly wire the NVIDIA chip to the display through a similar option, but on some designs there just isn't a display muxer that would let you do that (or it's not configurable).