Yes it has been done by a forum member. Here a post about a remodel on a 310 which had this feature: (http://www.airforums.com/forum...hlight=lcd+310
Also you can see pictures of the mount they created on their personal website (http://www.curtandmandy.com
). Click on "View Airstream" then click on "Interior Photos". I think it's about halfway down. Unforetunately this member sold their Airstream and has not been active for about a year. You may still be able to PM or email them however for more details.
One note on this. Many of the new high end motorhome manufacturers are getting away from overhead mounting position, between the seats, for a couple of reasons including ease of mounting, weight, etc. But the biggest reason they are starting to mount things lower (on furniture or on bulkheads) is viewing comfort. Sitting on a couch sideways looking up for a two our movie is not a terribly comfirtable viewing position (unless you're lying down on the couch - then it rocks).
We looked at the idea of an overhead mount based on what the owners did in this 310 makeover but opted for a furniture mounted solution across from the couch as it was cheaper, easier and provided better viewing for the kids while underway.