This is my 2nd working Joule Thief, part of a much larger top secret project that I'm working on. It uses a hand wound coil with a 2k resistor and a 2n2222 transistor for switching.
If you want a good understanding on how they work, read the Wikipedia article on "boost converter" first, since it is essentially the same thing. I used a variable resistor (or a pot as a vr) for testing purposes, you can see that there is a "sweet spot" when it comes to resistance, so don't just use any number from any schematic.
I've yet to play with the possibilities from the output of this. Since you've already got a high frequency voltage source, what's to keep you from adding more coils?
A 1 volt battery, as seen on the oscilloscope, is producing a pulsing 5.5 volts, which is common with what I'm getting from my dc-dc boost converter circuits (about x5).