I have a pair of brand new in box 21W/8554-00. I bought these for a project at the recommendation of Alec at RAAL. He said that hands down, these were the best 8" drivers every produced for a high-efficiency 2-way design. Being that he makes one of the best ribbon transducers in the world, I would say that is a pretty strong endorsement.
It looks as though these are no longer available, and as my memory serves, the last list price from Madisound was around $190/driver, and Solen Currently has 6 left at $219/driver. I am asking $275 for the pair, which I think is a terrific value, and much less than I paid.
Pics available via email.
These would mate perfectly with the Raven R2's that i am about to list.