I gather TV remotes, computer keyboards, cassette players and every sort of slightly out of date technology at garage sales. Most can still be disassembled with a screwdriver, then carefully sawed down to a useable thickness. The remaining sections are glued to half-inch thick industrial felt. Sharp edges are sanded down - some are intricately padded so they don't rip through the top layer. Damask napkins and tablecloths (also from garage sales) are washed and dyed and handsewn over the glued materials. Damask has a slight stretch, which allows it to 'give' a bit as I stretch it over and sew it down.
The sewing is really a variation of trapunto (sewing thick cords between 2 layers of cloth to create a raised surface). I always liked trapunto, and figured, hey, if you can sew cord between 2 layers, why not buttons? and safety pins? and even darning eggs, after I saw them in half....
in some cases, I dig out a bit of the industrial felt, creating a concave surface, to allow for a greater density of materials, especially with connectors.