I like the idea of a clear top, but how about this... Make the clear top be the sides too!
Basically, make it too long left-right, then have the extra length bent downward so you end up with an upside down U-shaped thing. This will give your binding posts something to screw in to.
Keeps the BOM count low, looks more professional, theoretically a little stronger than a top and two end panels.
Only question is, how much does it cost to get perspex/polycarbonate bent like this?