[leegreen]

If you want the look of a painted stock front bumper but want to save a few pounds I don't see why fiberglass would not work.
you'd want a nice smooth straight steel front bumper to start.

polyester resin is fine and cheap
1708 biaxial cloth would be my first choice, but any decent fiberglass place could give reasonable advise.

plug the bolt holes with bondo and sand
wax the heck out of it with mold release
do two layers well wet out
let it kick, catch the trim when the edges are pliable and you can slice them smoothly with a knife
give it a few hours to harden then break it loose from the bumper while it is still soft enough to distort (don't wait weeks)
if it seems too floppy put it back on the bumper and add more layers or glass in some wood or core material in back
fill the surface, sand and paint

or use the steel bumper as a hammer form to make a new one out of aluminum sheet!