Yes, I made one up from a sheet of plywood, cut to shape, thoroughly sanded down to get as smooth a surface as possible. Then coated it with one of the Ronseal tinted products to obtain the colour I wanted, and finally gave it some six to eight coats of varnish with a gentle sanding down between coats to achieve a glass like finish. Cost maybe two pounds for a left over part of a sheet of 10mm marine ply, and the rest was from my store cupboard of previously opened and part used tins of timber treatments.
Cutting holes into it to enable instruments to be fitted was easy using either a jig saw or a large circular hole cutter, and the extra thickness meant that the wiring inside could take a slightly easier route to the instruments without any sharp bends. To obtain a watertight seal I purchased some thick black single sided adhesive tape from the local DIY shop and which was fitted around the perimeter of the panel, and finally secured the panel in place with self tapping screws. The screws caused the tape to be squashed down which keeps the water out, and with single sided tape the panel is easily removed should I need to do so. It has now been there for the past four years, and apart from an occasional wash down with fresh water it has needed no other maintenance.