I stumbled across it while doing a Google image search.

Big Pilot Perpetual Calendar - Stainless, Charcoal dial - Limited to 31 pieces apparently. The strap in the photo is not original - apparently it originally came with a black alligator strap as per usual.
I know that the fliegeruhr.ch isn't COMPLETELY up to date (doesn't have the St Exupery Perpetual Calendar or any of the new Top Guns, for example)... but I've never seen a Big Pilot Perpetual with a charcoal dial!
If someone can shed some light on this model, it would be greatly appreciated! I am an avid Big Pilot fan and I feel somewhat embarrassed that I've never seen this one before.
Does anyone know of any other Big Pilot's that might not be on the fliegeruhr.ch website?