AtomSmasher,
I've got my plexi cut to size, but I'm petrified of drilling holes in it. My preference is to have screws, but I'm looking for the chicken little solution. 
Haha, that makes sense. But just so you know, the way to drill a hole in plexi is to set the drill in reverse. It takes a minute or two to make the hole because its basically just melting the plastic, but it makes a nice clean hole. Practice on a scrap piece of plexi if you have one.