Don't know if it would hold up to your demands, but Sherwin Williams has an industrial coatings line that is decent. Easy to use and dries in minutes, Rustoleum use to sell "Hardhat" spray paint, that stuff was great, but they dumbed it down, probably due to enviro concerns.
JB.
X2 referb'ed some parking lot light poles about 5 years ago. wire wheeled off all rust to bare metal, rolled on Sherwin williams industrial metal primer, then rolled on epoxy metal paint and they still look good 5 years later.