Matthew,
this is a very nice result. Do you have a pic how your setup looks like?
It's a pretty simple rig. It's a former Konica microscope adapter with a Nikon flange transplanted (note the hand made arrow for mounting), into which one can put basically anything that fits. The lenses in this case are from a multi-lens turret used for typesetting. The lenses vary in focal length and F stop but the less powerful ones can be used hand held. The one used for this is one of the smallest, giving about 1:1.3 magnification, with an f stop I'd estimate at something around 6.
There's no focus adjustment, of course, so one just moves the camera, but the rig is so light and easily swung around that it's surprisingly easy to work in decent light, or with the built in flash when reflection is not a problem.