Van's simple wingtip lens kit
I just ordered a set from Van's for my RV-4; they should be here in a few days. When I get them, I'll take a few pics and post them. I'll be sure to put a ruler in the photo so that you get a sense of size. From everything I've heard, they are pretty small; hopefully they will be large enough to enclose the 2" MR-16 lamps that I will be using for landing lights.