I got the plans to build it from a Dutch site, but it is pretty straight forward if you see the picture that they posted.
What it comes down to is that you can make the system as advanced as you wish.
I picked up an $6 soldering iron from an outlet, took it apart and replaced the insides.
Bought a light dimmer for $10 and then some connectors and wire also some $10 to put it all together.
I had an old transformer that had been used in a machine for photographic equipment. The foot switch I did not put yet, but I got one from an old sewing machine.
I used a wooden winebox to put all inside, but I'll replace that if I find something more suitable.
The main component was the transformer and its case, which basically had all the material that I reused, a switch and so on. This is a link to an image which shows how to set it up, but alas in Dutch
https://lh3.googleusercontent.com/-4eHmw6rsUGg/VUfKQCfBQaI/AAAAAAAAETQ/d9WHn61kqgI/s576/weerstandsolderen%2001.jpghttp://cooltrain.be/index.php/weerstandsolderenThe most important is making sure from the beginning that all connections are fixed well.
If you want I can do a translation of the whole thing:)