I hate to throw a wrench in the gears, but there’s some oddball stuff out there, like 1-pole 225-amp breakers [also 4-pole versions, too.]
http://www.eatonelectrical.com/unsecure/cms1/DS29170F.PDF 1-pole 400A class-T pullout fuseholder with circuit-breaker dimensions—used in off-grid battery/inverter systems.
http://www.boltswitch.com/131.JPG {These are not FPE brand, although FPE did make 600-volt industrial molded-case and air-frame circuit breakers. They did not have the widely-publicized “no-trip” problem.}
