Ok, so a while back, I saw this tutorial by =Fenris-the-Red-Wolf and was inspired. Of course, I neither worked up the time nor effort to do anything about it for two years, but I have finally worked up the energy to make them, and I'm quite proud of the fruits of my labor.
Ok, thats a lie. I am incredibly proud of them.
They are made from a whole host of stuff I had lying around - a couple of jam jar lids I had to drill through, some capnuts, leather from an old file, wool from the inside of an old laptop bag, and, the items I'm most proud of finding, green glass lenses from a pair of novelty beatles glasses (gotten from a fancy dress shop).
These are simply brilliantly done. I've been sitting on Fenris' tutorial for a while but might get round to making a pair this summer. I do have a leather file, myself, but I am reluctant to cut up a genuine antique. Once again these are wonderful - the best I've seen so far.
Thanks! Though actually, you don't. I thought I wanted the pair from the tutorial, but when you actually started making them you find yourself wanting to put in your own personality to it...
If your hearts set on glass, though... look in costume shops for the John Lennon style glasses - they're the perfect (5cm diameter) size.