
UPDATE:
It appears 20th Fox is moving fast on this one-
In a Hollywood Reporter exclusive, it appears Jeff Wadlow, who just finished Kick-Ass 2, set to release in August, has been tapped to writer and possibly direct X-FORCE for 20th Fox.
Well, that didn't take long. Worth noting also, is the fact Warpath, being played by BooBoo Stewart in the upcoming X-Men: Days of Future Past, is a key character in X-Force. Maybe DoFP will lead into or hint at this?

ORIGINAL ARTICLE:
Apparently, the X-Men fan site aptly named X-Men Films has picked up on our old pals at 20th Century Fox registering a website under the name 'X-ForceMovie.com', and movie companies don't usually do that unless their planning to make a movie.
(Unless that movie is Soul Calibur with Anthem Pictures which had 'SoulCaliburTheMovie.com' registered since 2007 and recently JUST went up for sale again. But you know, whatever)
Anyway, apparently the dude famous for drawing mis-proprtionate buff guys, Robert Liefeld, creator of X-Force, took to Twitter forever ago hinting about future Cable/X-Men stuff, since Cable is a member of the X-Force:

X-MenFilms also pointed to a statement made last year by Marvel "Consultant" Mark Miller:
“You have to remember that Fox grabbed the X-Men back in the ’90s because it was the biggest franchise in the world. So X-Force or Cable or Deadpool — all these amazing characters are things we haven’t really gotten to yet. ‘X-Force’ #1 was the second biggest book of all time behind Jim Lee’s ‘X-Men’ #1, so there’s an immediate brand recognition to that stuff and a build in fanbase. You go to any convention in the world, and you’ll see 20 people dressed as Deadpool. In a lot of ways, these are Marvel’s coolest characters, so I want to remind people of that and build on what we already have. I think there’s a great foundation, and just from basic conversations, we’ve come up with ten movies we could do. These things cost $150 million each to make, so we have to pick and choose what we want to do.”