[blackguardx]

Machining doesn't work that way. The groove in the laptop is done with a round nosed end-mill. It makes the rounded profile and creates lots of chips. Those chips are then melted down and made into something else by some other company.

[tesseract]

Machining still doesn't work that way, but on the Air the cutout goes all the way through so there is no need for a round nose mill specifically.

[blackguardx]

Sorry I haven't seen one. I only have an aluminum macbook