From Jedi Defender:
Rumor: A 6" Exclusive for SDCC 2013?

Well, it sure didn't take long for new rumors to pop up. Our sources are telling us that The Black Series 6" line may make its debut before August at a cerain large scale west coast convention. Always in motion, the future is (and this year moreso than others) but hopefully we'll get more info at the large scale east coast event nine days from now.
It's only a rumor at the moment but I'm sure it'll happen. Whenever Hasbro launches a major new line or sub-line they love rolling it out with an exclusive figure at San Diego Comic Con. I do worry given the lack of Darth Vader in the first wave if they might roll him out as an SDCC Exclusive. Hopefully whoever they choose they keep a few things in mind. People are going to go crazy pants for this line. And they better produce enough so there will be plenty to be sold on Hasbro Toy Shop after the Con.

If they do release someone major like Darth Vader... hopefully it's mostly just the packaging that is unique. So that people who can't get to SDCC or can't buy one for a sane price from HTS or the Secondary Market will still eventually get the character. Or they could do something like R2-KT for the SDCC Exclusive. Something that's more niche and won't tick the new eager collectors off if they can't get it.