In the automotive paint world they have paint color matching machines. You can take a example of the color you need to a automotive paint supplier or a body shop and these machine will read and put together a color mix to match. You could then use an air brush to apply it. There was a company that advertised in Electric Radio magazine who supplied paints to match the colors of various vintage radios I cannot remember the name.

http://www.eastwood.com/paints/airbrush.html