I've got a nitrogen tank set up with a 25-400 psi reg and gauges, and 500psi rated hose for sale, $125.00.
Nitrogen doesn't freeze up like CO2 does, but you can't carry as much N as you can CO2. It holds enough to air up tires, but not enough to run air tools for very long. Adjusting it to 400 psi re-seats tire beads pretty easily.