You can get away with MUCH cheaper than this for power distribution.
I built my block out of modular items that mount to a piece of railing in my control box. It handles 50A and wires anywhere from 22 gauge to 8 gauge in size.
I listed part numbers (from mouser.com) for the items I used here:http://www.homebrewtalk.com/f51/my-herms-build-ready-criticism-173077/#post2003768
Even with shipping added in, you can build the power distribution block (and give yourself room to easily expand it later) for about $15.
Mouser might also sell switches equivalent to the ones you linked if you want to shop at just one place.