This lens sold for $20,000 yars ago and Leica offered it with a free Volkswagen (true, I think someone has the ad!)

Anyway, I bought on a lark years ago, never used, but looks clean glass is great and is really an R mount.

This lens is only one half stop slower than the 800mm 5.6 Modular, and may even be sharper (though harder to focus. Not your walk around lens.

There's one on ebay for $8600. I have it is a nice original aluminum case, and I think there was a slot for the camera (likely the R4s or some such).

This one can be had for $5999, and I will pay US shipping.

I'll post some pix later, but this will go FAST so let me know!