I have a bezel and knobs coming, but this is what it looks like so far:
The cutout process varies according to the panel material. For plastic, first I draw and outline of the LCD and then I drill 4 holes at the corners, but inside the lcd cutout you've drawn. I then put a T-square to align with the line drawn along one edge of the cutout. I then put the panel and T-square in a vice and saw along the line, relying on the T-square to prevent me from "coloring outside the lines". After I've made the cut, a few passes with a file and that edge is done. Rotate and repeat. If it's metal, I align with the jaws of the vice with the LCD outline and drill a series of small holes. I then use a hacksaw blade to cut the line and finish with a file. The Dremel would probably work wonders here instead of the file.