Didn't think home made steel panels were a realistic possibility.
With the availability of and relative ease of access to CNC and laser/water-jet cutting, I'd say they are very realistic. Probably not cheap, but realistic.
Definitely not cheap in low quantities, but they are certainly possible. Last year, I ordered 30 joystick mounting plates (mount the joystick to the plate, then mount the plate to a wood panel), with a center hole and 8 threaded studs. They were $10 each at that quantity. I needed a couple of different plates, so I got quotes last week. In quantities under 5, the same plate is $38.40.
A standard layout would be 16 holes and 8 threaded studs. Add in a trackball, and it is 4 more studs and a hole.
It is still only one setup though, and that is the expensive part. If there is bending to shape at the edges, that would be a bit more. I would guess that it would be about $100-150 for a 24" panel.