personally i would alter the desgin of the handle so that it is a screw on part that will simplify the probelm with covering it.
if you are willing to NOT use foam but just to use MDF it would be relatively straight forward to make.
plain rectangle base, 1/4 inch hardboard or aluminim panel. then glue/screw on 1/4 inch mdf cut to you oval shapes, fillet the edge with fillers then cover in black vinyal.
much easier to do than foam, and you could do it yourself.
i have made these door cardds fro my bug
i also made these but i didnt use them after i fitted a roll cage.
i can get the white ones made in fiber glass, £100 the pair.