Keep in mind that above 1200 amps, it will be called a bolted pressure switch. Seems like it boils down to getting one of those, a circuit breaker and enclosure, or breaking it up into several smaller service disconnects (in which case you could use circuit breakers, or regular safety switches because you dodge the GFP requirement).
Do you need metering provisions?
Seems like a supply house gear guy could set you up with the most affordable option.
Ethan Brush - East West Electric. NY, WA. MA
"You can't generalize"