Here's a link to one supplier
http://www.texasindustrialelectric.c...lel_switch.asp
One comment - in order to pass the same energy, a lower voltage circuit needs higher current which in turn needs larger cross-section wiring and contact parts. In other words a 12-24 series parallel switch may have problems working in a 6-12 volt application. As well, the solenoid in the switch may not work as well as it should.
More links that may interest
http://www.qualityengineeredcomponents.com/?page_id=564
http://www.antiqueautobattery.com/accessories.html
http://www.stovebolt.com/ubbthreads/...&Number=710615