What kind of paint could I use on glockenspiel keys that would not interfere with the resonance, or would painting glockenspiel keys deaden them too much?

I was hoping you could answer a question about building a small homemade glockenspiel. My a cappella group group is planning on performing a song that has a little keyboard part in it. I'd like us to play that part on what should look like a child's toy glockenspiel--the kind with a single diatonic octave of rainbow-colored keys. I'm trying to find an already existing toy that's in the right key (E) and range, but I'm thinking that I'll probably have to build one out of already existing keys. My problem is that if I were to cannibalize other toys or order parts from real glockenspiels, the keys might not be painted in a sufficient range of colors to get that rainbow effect seen in a kid's toy, so I'll have to paint/repaint them myself. My question is this: What kind of paint could I use that would not interfere with the resonance, or would painting glockenspiel keys deaden them too much? I'd like the look of a cheap child's toy, but I want the keys to sound nice, more like a professional instrument. Thanks!

Toys - Hohner - Glockenspiel Instrument by