I built new panels out of 1/2" plywood, and put hinged panels with locks on them where the existing panels are. I ordered the locks all keyed the same, since I put an extra door in the driver's side between the roll bar frame bars. This allows easier access to the storage space. Covered it all with outdoor carpet. It looks good, and has plenty of storage space. If I had to do it all over again, I'd probably go carpeted aluminum or 14 gauge steel, just for the extra security.

I also built replacement front quarter panels from 1/8" melamene (same carpet), and added speakers and two storage bins. I put two amps in the front quarter panel area behind the driver's seat, where the rear window relay is. All the amps are out of sight and don't take up any interior room.