Any one can make them quite easily. The materials are readily available from Clarke Rubber and any wharehouse that sells plastic sheet (signwriters can probaly give directions for plastic sheet).
I use .07mm polypropylene sheet (its called the plastic hinge) for the base plate, its very hard to tear.
EVA or PEVA sheet is readily available from Clarke rubber for the pads.
The same place that sells polypropylene will sell PVC in 15mm thickness for screw inserts, just check the offcuts bin.
This image shows home made pads and back plate.
Just contact cement the pad to the back plate.
go for it