This thread has got me thinking. Why couldn't you just make your own out of acetate?
So, I've mocked up the HVAC controls and pulled mine apart. My laser printer is be ghey and printing seriously dirty prints - so I'll need to get it printed elsewhere.
But here's the rough idea, remove the plastic clear insert, replace with an acetate print of below, and put whatever colour card you want behind it, then illuminate as normal.
