Autocad

Drawing the gauge pockets is simple...in Solidworks anyways. Once you have the part, create new sketch on the face plane, draw your circle, then extrude cut through the material thickness. I wouldnt make these out of metal...the heat from welding the gauge pockets in will likely warp it all to hell.
Fiberglass is your best bet in my opinion. Hell, you could practice with fiberglass, get a mold made, buy some release agent, and start making them yourself without needing anyone else.