Here's a link to the write up for my "storage system", http://www.jeepforum.com/forum/f37/y...ite-up-596248/
I didn't use fiberglass, but I don't see why it wouldn't work.
Basically what I did was build two boxes that sat on top of the wheel wells, and used those as attachment points for the tonneau section. By using the wheel well boxes, the tonneau did NOT have to be notched around the roll bar, and it could be used with the hard top, soft top, or no top at all. And, as an added bonus, the side boxes doubled as arm rests for rear seat passangers when the back seat was installed.
Granted, the YJ fender wells were squared off, which made it real easy to attach the boxes, but with a little creativity, it shouldn't be to hard to adapt the idea to a TJ.