Do you think the NVIDIA GTX 680M will make it into the 2012 MacBook? why or why not?
No chance, uses too much power and produce too much heat for the mbp to handle, maybe it will be used in the 27" imac as BTO. A mid range GPU is more sensible choice for mbp I think.
I don't think Apple really targets gamers with their notebooks. They tend to use more midrange GPUs that use less power and make less heat.
As far as performance expectations go, Apple never aims to serve the top 5% of hardcore gamers out there. Apple's business model is to cater to the much larger mid-range consumer market. There's no chance they're toss a top-range GPU in their laptops.
What % share do Apple have of the laptop market world wide (not just USA) I wonder?