In March 2011 it was announced that this would indeed be the case: Solaris would reprint the two existing books, The Mark of Ran and This Forsaken Earth, in an omnibus complete with the brand-new third and concluding volume, provisionally entitled Storm of the Dead. To make this possible, the Bantam editions had to go out of print and Bantam had to agree to give the rights back to the author.
Unfortunately, since then there has been radio silence on the matter. It can now be confirmed that the Sea-Beggars omnibus is on indefinite hold, and may not appear at all. This is due to additional contractual and legal wrangling. Whilst Bantam UK gave up the rights as planned, Bantam Spectra in the USA refused. A check of Amazon.com reveals that the two existing Sea-Beggars books are still in-print and selling in the United States, which is presumably why Bantam Spectra have decided to hold onto the rights.
If the books are still selling well enough in the USA for Bantam to want to hold onto them, this would theoretically suggest that they might be interested in publishing the third and concluding volume as a stand-alone novel. However, this is apparently not the case. If the books are not selling well enough to warrant Bantam publishing a third volume, then it is unclear why they would want to hold onto the rights to prevent the series being completed elsewhere. If the series is selling well enough to warrant hanging onto the rights, then it is unclear why Bantam would not be interested in publishing a third volume as well. As it stands, it appears that the fans who have been waiting seven years for a conclusion to this series will have to keep waiting due to the inscrutable machinations of publishing houses.
On the bright side, Solaris are reprinting Paul's first three, stand-alone novels starting in January. Here's an art blog where they talk about the process of the creating the splendid cover art to A Different Kingdom. We may also get some news on new material next year as well.
