http://www.tvinsider.com/article/64833/the-cw-boss-on-supernaturals-long-run-i-dont-think-anyones-out-of-juice/

Says CW president Mark Pedowitz: "I can't tell you if [the not-yet-ordered] season 12 is the end, I can't tell you if season 15 is the end. I can't tell you it won't outlast my tenure at The CW. My guess is, it will outlast me."

Good to know. Hope they keep coming up with new ideas for the show and that the guys want to keep playing the Winchester brothers.