I've been searching for a decent case for my Macbook Air 11" for a while now, and despite my willingness to buy, I have not found anything suitable. No designers are creating cases for the 11" (very annoying to see Mulberry, Liberty, DvF, Paul Smith et al offering cases for every other model), and all the cases on sites like Amazon either look nasty or are very corporate and on Etsy they are too homespun.
I decided that a good stop gap would be the American Apparel leather pouch (they offer 3 or 4 sizes), it fits the 11" - just. With a bit of a wrestle you can get it in and out, but thanks to the zip it is quite an undignified operation. Once I find the perfect case or cover I can requisition the leather pouch as a clutch bag because the colour is fabulous, especially against bright hues.
Sweater - Whistles
Jeans - Zara
Shoes - New Look
Clutch - American Apparel