Below is what I used for my web.config using an azure website.
Note 1: it is similar to what Mickey said he would provide, but I added mime entries for .json, and .unityweb, which my application used. Check your files on your "Build" folder to see if you need others! :)
Note 2: The <? xml header line, which is shown as the first line by some sites, was not necessary.
What happened to "The Road Ahead" with LightSwitch?? Are you ever going to comment? Is it dead, in production, cancelled because of litigation? It was a great product, but frankly now tarnishes your reputation that you won't tell developers what happened. Can't you say something, or Open Source it, or ... ?
I've seen the User Voice repository on the MS campus. It resembles of Cave of Swallows in Mexico. You throw a message in, and nothing comes back except a thud. Except if the message contains XNA, Silverlight, or LightSwitch; in which case not even a thud is heard.
Great concept guys, and congratulations on all you've done... but Holy Smokes!! (and I'm pretty sure you'll agree with me), this should have been a 30 minute presentation. A little presentation planning please.