I think you'd agree that James Gunn is one of the few people involved with Marvel Studios, to make the time to interact with fans. Another person who is always in active dialog with the fan base is writer and director Drew Pearce (Iron Man 3, Sherlock Holmes 3, Mission: Impossible 5) . If you don't remember, Drew co-wrote Iron Man 3 with Shane Black and directed the All Hail The King One-Shot (which he also wrote) short which teased the real Mandarin and setup Luke Cage's Seagate Prison. Pearce also penned the script for The Runaways movie that was effectively put into development limbo.
Drew sneakily added a small Easter Egg to All Hail The King, which hinted to villains and mob families connected to Frank Castle. Seagate Prison is currently holding a mob boss responsible for the murder of his family. Pearce has responded to the possibility of doing work on something involved with The Punisher. Pointing-out a preference to the runs from Gregg Rucka and Matt Fraction. Along with mentioning the backstory of Rachel Cole, Frank's recent sidekick. This is by no means confirmation he is or will be doing this in the future, but it's lovely to hear that Pearce doesn't hate the idea.
@_ChristopherM The Rucka and Fraction runs are the ones I'd be really into. Love the Cole storyline (and the way Checchetto draws Frank).
— Drew Pearce (@mrdrewpearce) September 16, 2014
At this point, we have zero indication that Marvel will indeed move forward with a Punisher series or even One-Shot, but the fan demand in clearly there. Even with the Russo Brothers jokingly mentioning someone being behind the wheel in a couple of scenes of Captain America: The Winter Soldier being a strong candidate for a One-Shot. Most assume they are speaking of Frank Castle, but could be just a joke from the comedic filmmakers.
"The man who drives that truck," Joe deadpans, joking that the driver is a candidate for a future Marvel One-Shot, "Is very highly trained. He thinks on his own terms. He's got a plan and a very specific skill set."
I wouldn't be too shocked if saw a pre-tragic Frank being a special ops operator in the former SHIELD, in the third Captain America film. Castle has ties to both Fury/Rogers and anything is possible, now that Marvel is able to use characters where ever they want. Another possibility is showing-up in the Netflix series, Daredevil making the most sense. A lot of people are expecting a Punisher series being considered for a second wave of Netflix shows.
We've had a couple of actors even try to put their name into consideration. Frank Grillo wanted a shot, but that might be an issue as he's already played villain Brock Rumlow (Crossbones) in Winter Soldier. Another actor is a bit more unlikely, as Milo Ventimiglia (Gamer, Pathology, Heroes) took to Twitter and reveal his campaign for the role. There has even been calls to bring back Thomas Jane or Ray Stevenson, but I'm not sure that's the best idea.
A couple of other actors I wouldn't getting into the mix, would be Clive Owen (Children of Men, Bourne Identity, Inside Man, Killer Elite, The Driver, Sin City, Shoot 'Em Up) or Superman candidate Joe Manganiello (True Blood, Sabotage, Magic Mike, Spider-Man). Owen would mean we'll have a third foreign actor playing Castle, which I'm not opposed to. However, it's likely the reason people champion Thomas Jane for the role.