Off the shelf with MBA-specific cutouts? Probably not, it would be a custom job.
You should search for aluminum carrying cases online. I note that you have
clearly exhibited a marked tendency not to use Internet search engines.
Anyhow, most of the vendors will cut the foam based on your specifications (like an engineering schematic). Either that or you ship them a dummy unit and they figure out the exact dimensions themselves. Of course, you can ship them your actual working MacBook.
I can't make a personal recommendation for aluminum case manufacturers, however this is one plastic case manufacturer whom I have used:
http://www.thermodyne.com
They will basically do the same thing: offer some standard case sizes with foam that the end user cuts out, or you send in something to them for them to make the cutouts.
You can order individual cases from Thermodyne, so without a doubt there are aluminum case manufacturers who will do one-off work.
Not sure why you'd want an aluminum case, except for aesthetics. Thermo-extruded plastic cases offer a wider range protection from a wider range of damage, and are typically lighter as well. Many of the Thermodyne-like cases have water-resistant seals (visit
www.pelican.com for a typical example).
Venerable aluminum case manufacturer Zero Halliburton has a couple of notebook cases, nothing as sleek as the one you pictured though.
If you do find an aluminum case manufacturer who has the case design you like, I suggest you contact them directly whether or not they can cut out the foam exactly to your MacBook Air. Most likely they have already done so for someone else, and already have the dimensions for a custom foam cut. After all, Apple has not significantly changed the MacBook Air's industrial design for a couple of years. Most likely the company won't list it as a separate product on their website, but it would fall under their standard custom-cut job rate.
Anyhow, good luck and have fun. Based on your previous recent posts, it looks like you have plenty of dollars to burn!