Where would the best guy be to custom paint a throw?
Metal throws are generally anodized but can be painted. I think bcmaddog does it. Haven’t seen him on the forums for a bit though. There’s likely others who will do it for you also.
yoyospirit and mullicabob do powder coating which is probably the most practical way of painting a yoyo
If we’re talking metal yoyos, then yea it’s certainly the most durable. Not going to get the detail you would in a real painted piece, but you can get some designs/artsy stuff in a durable finish.
If you’re doing plastic, you dye some pretty crazy stuff (again nowhere near painted detail), or if you have a clear body you can paint the inside.
Outsides of yo-yos can be painted, but they’re not going to be super durable long term.