I have wanted to try making a set from aluminum plate.

Should be fairly easy for a diy with fiberglass, making a mould from original in plaster, fine sanded, laying the fiberglass,add the gel,then sanding to perfection,small tube and screws to build the studs covered with resin,add appropriate rubber washer and voila.
That`s the way i`ve proceeded when i`ve lost one of mine, borrowed an original from a friend who had the same bike.