Thank you everyone for the suggestions! I did some experimenting with gold acrylic paint I already had, and I think that's the look I will use (middle sample). It flexes beautifully and doesn't crack.
I wanted to use leather because this is for a She-Ra costume (if you remember her from the 80s), and I wanted to make the bracers, belt, headband, etc all out of the same material so they'd match exactly. The headband doesn't need to flex much, but the bracers and belt certainly do. I've also just started leatherwork, having made a few items (bracers, belt, pouch) for another costume last year. I really enjoyed working with it, and I love the "authenticity " it gives a design.