Painting the various knobs and switches was one of the first jobs i did to the interior of my Rover. As you say it makes a difference between a well worn and a smart interior. If you can't find good switch backings you can ask a print and label shop (i am not sure how to say this correctly in English but you get the idea) for some copies. I have a few custom to made to compliment the A/C controls in my car. It is not expensive or difficult, but you have to provide a dimensioned draw in WORD, and finding the correct fonts might take some time and patience.