[Update: Here's a gallery of photos from the big event (on Facebook).]
Image taken last week with my D90 (with 50mm f/1.4) and an external flash shooting through the famous $0.02 mini macro studio:
I hand-held a Nikon SB-24 flash connected via a wireless trigger over a folded sheet of paper that acted as a giant diffuser for the ring, which I simply placed on a 'seamless' piece of cut computer paper (standard copier paper.
You don't need to go expensive to have the finest results. No doubt about that. You just have to do things with care and love, and a little ingenuity.
Here's a setup shot: