radio shack sells 50K pots for a few bucks. Then just need a microswitch. I've thought about making my own low profile one but instead I'm going to try to rig up a new torch style one that allows you to easily adjust the amps from the torch. There's a few companies with designs out now but they all seem to make it rather hard to adjust the amps and keep the torch steady.
but anyways long story short, just a 50K pot and microswitch and you can make your own...just need to get a hold of a connector
http://www.ideadevgroup.com/