There is a script written for Conan 2, which of course will never be made now, but it was based on one of the REH stories, possibly 'A Witch Is Born'. I read about it ages ago, pretty sure that is the story they adapted.
They used a bit of that story in the Arnold movie, where he is left crucified in the desert by his enemies, and he bites a vulture in the neck.
One of the posters over at conan.com said he'd read the Conan 2 script, but I guess he got a copy from an inside source, but who knows, it could be floating about on the net somewhere.
One poster over there made a good point about this movie, that it doesn't have any sense of mystery in the tale. Which was always a large element of enjoyment in the REH tales, Conan stumbling into some supernatural situation and trying to figure out what the hell is going on...the new movie was just a series of fights basically, as he went on a revenge rampage.
Tv series is the way to go. I can't think of any movie that flopped so badly that got a tv series afterwards though, but at least there is the Milius/Arnold movie to hold as an example, which was a major hit back in the day. So they can see that the world can connect with audiences in a big way.
And as Roy Thomas said on the Conan doc on the dvd, back in the 70s Conan was selling as many comics as Spider-man and the Fantastic Four, done right, the character could be that kind of phenomenon again, except this time on the tv screen.
This movie was a rush job, which is a shame for Mamoa, as he did a good job portraying Conan.