Trax, if I understand correctly, You want a metal pannel that hasa compound curve, with the sharp edge that you would expect from a metal pannel, or something that looks like that.

Fiberglass would work, but it going to take a lot of work to get what you want. It's kind of like making jewelry. To make a ring, you start with a block of wax. You carve and shape it to exactly what you wan't the final piece to look like. Then you invest the wax in a plaster of paris type stuff to make a mold of the piece you want. You then burn out the investment in a kiln. The wax is completely burnt out and you have a mold that you fill with molten metal that will look just like the wax you carved. Thinking along those lines, you could carve a plug that would be the piece you wan't. Make sure the details are them. From that plug, you would coat it with a mold release and then lay up a fiberglass covering on it. This fiberglass would be the actual mold that you would lay up your final part in. As much detail as you want can be included in the plug, and the final product will look like that. You will probably have some air bubles to contend with, but they are a minor issue. It is a lot of work for a one time project, but in case you want two or three, or more, you still have the mold.

This isn't a path I would take, Ihate working with fiberglass.I would just use a filler and build it up and shape it to what you what. The balsa filler will be to soft, but body putty for autos will let you file and sand to the shape you want and they will take most any paints you want to use after. It will probably hold up OK, but if you want a realy crisp sharp edge the won't chip wiht handeling, metal is the only way to go. I woudl suggest getting a roll of the aluminum duct tape and playing with it to see what you can come up with. Once you find how it works, then you can decide if it will do for the task at hand.

Don