Square-D catalogs 30+amp 4- and 6-pole safety switches, but are "heavy-" {600V} not "general"-duty.
http://www.squared.com/us/products/safetysw.nsf/07a0210021262d45862564b5006e4f84/fa3cba46f7a9519d852566c50073d833/$FILE/3100BR9801R601.pdf