Powder coating will last way longer and be more resistant to scratches than any wet paint, I'm not sure if there are glossy powder coat finishes though.
Powder coating will work fine . A lot of Drums including ours are painted with car engine paint which is good to about 600º
you can get glossy powder coat
I'm going to have my dreaded-red-liner drum sandblasted at a powder-coating company near my work. If they offer me a deal on finishing I might just take them up on it.
Mine is powder coated, I love it. It's the high temp black (traeger style) with a relief finish. I probably cook on this thing more than any of the other four pits out in my Meat Manger.