Graham,
I cobbled together my own bending iron setup. For the heating element, I used an electric charcoal fire starter. It's a narrow hoop attached to a handle. I bent it in a vise (squeezed it together) to the point where I could shove it up inside of a piece of 2" pipe. To control the temperature, I used a dimmer switch and mounted it with an electrical receptical in a junction box. I then mounted an over thermometer to the front of the unit. Here's a photo:
After this, I found that I needed an extension for tighter bends. At first I tried using a reducer from 2" to 3/4" pipe, but the reducer added a lot of mass to the bender and moved the 3/4" nipple out far enough where it too way too long to heat up. So, instead, I drilled a hole through the top of the 2" pipe and through the 3/4" nipple and mounted it to the top inside of the pipe. I lost the thermometer when I did that, but I had already scribed a couple of lines on the dimmer switch plate so I knew where a couple of temp settings were -- the two I used most often (280F and 300F).
Best,
Michael