Ever since i have sold my oakleys theres a pair that i miss the most, which is X-metal/ruby penny, i think that is my holy grail if i ever start collecting again.
Copper/vr28 Penny. I have one, but the flex coupler has fallen out so it is floppy and unwearable.
A few years ago it was the ruby New Zero with the Ducati cut. I saw one for sale then but none since. Now I know about the limited lifespan of the thin Zero lens, so it's not so important ....