Sennheiser has been shipping the MKH8000 series for about 5 weeks. Although, not many accessories are available yet. The first few batches to land in the US went mostly into the broadcast industry (film sound, network TV, etc) for evaluation. I know for fact they were used on the film Spiderman 3 and by Fox during the World Series. I borrowed the pair I used last weekend.
As I have said before, according to two of my wholesalers, these are still not available in the US.
It makes sense that the pair you have are borrowed from someone in the broadcast industry, as they often get gear before it is released to the general public.
In another thread a retailer has them listed for sale, but when asked if he has them in stock and if they are ready to ship, he gives no answer, which leads me to believe that they aren't.
I'll make another call to my contacts later this week as I think I will pick up a pair of the 8040's.