There's no way in hell we're going to get a Punisher movie in theaters any time soon. There's just too many other characters and stories they could mine that would fit the mold of the MCU better than Frank Castle. That being said, I could see him show up in someone else's movie. I remember reading rumors where writers considered inserting him in The Winter Soldier. I'd love to see him show up in one of the Netflix series, perhaps on the way to getting his own. He'd work so much better in that format. Wouldn't need a very large budget, could go as brutal and violent as he needs to be and the limited nature could attract some quality talent.