Over at prometheusnews they seem to have dug up some interesting claims made by website called Nexusnews.
Here`s their quote:
According to our insider information: Prometheus 2 is under works, and it planned for a 2014/2015 release. The filming will start shortly this year. Currently they are at the Planning stage, where they lay out the entire plan on how to film the movie in the proper order and how to achieve some of the special effects described in both the scripts (currently in progress) and the concept arts. Later this year there would be production videos showing the progress that they made thus far, and how they didn’t waste any time.
Their ideas are very solid, and answer several questions that were asked in the first movie. Although several questions will answered throughout Prometheus 2, the story would be based on two main plot lines that were left off from the last movie. The first and most important is where will Dr. Shaw and David go, and what will they find there. It has been speculated that Elder Engineers that were cut from the last movie will play a huge role in the sequel. They were probably cut from the main movie for the same reason. Because it was thought that perhaps they need to be reworked, and represented in a whole different way.
To be taken with a grain of salt.