Well, finally! The stuff she got is called: Art Alchemy Opal Magic paint. It comes in two colors, Violet/Green and Pink/Blue. I brushed some on a plastic fork I had painted gloss black:
The Violet/Green was what I was thinking would be good to try for the solar panels. If you paint on a black background, you get an opalescent violet color. Paint it over white, which I didn't show here, you get a kind of turquoise green. I'm thinking the finish might be a bit better if sprayed, but I didn't go through all that effort yet.
On the tine-end of the fork, I was trying some other stuff she got, called Rust Effect Paste from Finnabear. It's kind of gritty acrylic paint that comes in three colors for a more-realistic rust effect; brown rust, red rust and gold rust. It comes as a kit. I might try some of this on the FT-17 I'm working on now.