An overlay is very simple to make. You'll need glass cloth, carbon fiber cloth, ply peel and epoxy. West Systems look great. This is an easy way to do it without vacuum bagging and any other exotic process. Just requires a little more elbow grease and no specialized equipment.
Cut the cloth oversized to the panel by a couple of inches. Cover the panel with clear packing tape. Make sure to get the edges.
On the taped panel wet a layer of the glass cloth. Add the next layer of cloth, wet it out. Repeat with the carbon cloth. Use a brush or foam roller and work the epoxy through the cloth. If you have a stippling roller, even better but is not needed.
Cut a large piece of ply peel and lay over the carbon and work the any bubbles out. If you have a piece of glass (window type) lay over entire structure. Doesn't have to be glass, a large piece of particle board will work. If you use particle board, lay a piece of wax paper over the ply peel. It just needs to be something as flat and heavy as possible.
When all is set, put some weights on it evenly distributed.
After the epoxy has cured remove the weights, flat piece and peel off the ply peel. Don't remove from your panel yet. Brush on another layer of epoxy and spread with a squeegee or your wife's credit card. Just get the epoxy to lay on. Don't add too much. Just trying to fill the weave left by the ply peel.
After curing, block sand with 240 grit wet/dry. This will give you a read on the surface. If you have any real low (you really shouldn't) spots add some epoxy. After block sanding with 240 and getting a nice surface, sand with 320 w/d. If it looks good, go to 400 w/d sanding wet. Don't worry if you sand into the carbon, that will be dealt with later. Remember this decorative, not structural.
The key is to get as flat a surface as possible but little voids won't matter. You're going to be cutting out lots of it anyway. You can check where your instruments will be for validation.
You can keep going and sand down all the way to 2000 grit and nearly polish the piece. However the easier way is to get to 400 grit and then clear coat. You can use Krylon epoxy clear for this. The clear will bring out the carbon and you'll have a nice overlay.
You can Dremel the edge around the metal panel and then sand. If you try to use a band saw, your blade will be gone in 5 seconds!!!
For attachment to the real panel you can scuff the metal and epoxy or use nut plates and fasteners.
Almost took longer to describe than to actually do!!! Let me know if you have any questions. You can contact me direct and I'll email you a couple of pictures of the panel. email@example.com
Hydro dipping is a nice process but is not cheap. It also has to be clear coated for protection.