Looking for Sign pannels

I need to find a raised lexan or plastic insert for a 4 x 8 ( not a flat sheet of lexan) lit sign box, can anyone tell me who sells them. I do not do lighted signs but have a good customer in need of a new one that has been damaged. Thank you for any help you can give me.
Ray@rprintingusa.com

Ray McLendon
R Printing
ray@rprintingusa.com
r_printing@cox.net