01-25-2010, 10:03 AM
If you are able to get into the wall to strengthen the joint, then you *may* be able to get away with the floating shelf approach. But anything face mounted, even into the studs, on top of the drywall will likely not be strong enough. However, you can also reduce the weight of the benchwork by using (for example) steel studs and foam decking. While this would not be strong enough to support a lot of weight, at 50"+ off the floor, I am assuming that no one is going to have to walk on it.
Andrew
Andrew