Beauty of the beholder
In typing this from a Black MacBook, you might see where I'm coming from. I've never regretted this color choice, and love it all the more.
If not an entirely black color computer option, then the black bezel on the MBPs seems to me a decent compromise. People will surely favor different colors, but black perfect in being a neutral surround for that viewed. So, yes, I would very much favor some method for a black bezel on the MBA.
Some thoughts on that. Most products in the Mac aftermarket reflect the same high standards as the computer, and that is the standard one should aim for and meet. Something applied to the MBA bezel may work, but it need fit exactly and look OEM. The cutout for the MacBook logo at the bottom you suggest is a case in point; just wrong, with a better solution, as others have suggested, in covering that type entirely. The best solution, and one your competitors may well introduce if you do not, is the same exact logo printed or embossed on the bezel cover, looking no different than if Apple put it there. If that seems daunting, then no less than the necessary step from hobby to a viable product many might buy.
For those so interested, there are some good options if one would prefer something other than the standard color and look of the MBA. But be forewarned you'll probably choke on the price:
Computer Choppers
http://www.computer-choppers.com/index.html
ColorWare
http://www.colorwarepc.com/p-250-macbook-air.aspx