skr - I my case there was some welding to make the thickness of the metal and to make the brake and shifter rods longer. It is really a simple process (for me anyway).

I used 1/4" X 2" SS plate (2 peices welded together for 1/2" total thickness). I think the total height of the piece is 3/4". Used the stock brackets to space my holes and actually turned them up on the end to have a more comfortable position as the tops of the pegs are flat. Maybe you can have someone in a machine shop make it. I would not go under 1/2" thick as it is only supported by the bolts where the original pegs were mounted. I can make a mockup out of wood and send it to you if you would like me to. Of course you can change it and make it different....this is only one option to consider.