How practical is the sliding bunk over cab in Class A's?

The best new drop down bunk I have seen will be on the 2015 Coachmen Sportscoach Cross Country 404RB. It's called a "salon bunk". It's a 12 foot long bunk that drops down from the bulkhead over the dinette and sofa. Long enough to sleep 2. When up it's totally concealed. It's a belt driven mechanism. I can't find any pics on line but it was featured in the new Motorhome magazine (pg 52). This could open up a whole new range of bunks essentially combining drop down and bunkhouse ideas in one. I love it.