wanted to plug my rMBP to a Samsung 4K UHD screen they had a full size display port via my mac's mDP connection. So I went looking for a cable that goes from mDP to DP and went to Best Buy, Apple, radio shack and couldn't find any. That's really odd to me that these cables are non-existent in stores? Why is that? You would think that with all the mDP macs out there and displays with DP out there that there'd be a need for such a cable?