Alright already. Here's what you need to do. Figure out a type of wood that matches your decor. Might be maple, oak, cherry, whatever. Go see your local custom cabinet builder and get a piece of 3/4" cabinet grade birch plywood and make a backpanel that:
A) securely fastens to (2) studs but preferably (3).
B) Leaves a reveal of 2", 3" or whatever you think looks nice around the top, bottom and sides of the plasma.

Then, wrap that piece of plywood in a veneered piece of plywood in the wood species you chose. Get this from your cabinet builder too. A little trim, in the same species of wood, around the edges and viola. A custom install that matches your decor and a plasma panel that might just stay in place.

Now, BEFORE installing the plywood, run any cables you might be needing ie coax, component video cables, whatever. You can cut the drywall/plaster as the plywood will cover them up. Hell, you might even want an electrician to show up so you don't have a power cord dangling down the wall. Have him install a Panamax in wall to power the panel.

When your all done it will have the custom look and a safe install.

And you thought your local custom installer just hooked it up and skated out with big money in his pocket. THIS is why we are custom installers. Custom solutions for professional looking results.

Hope this helps.