Rumors have just started up for Space Marines over the last few weeks, and the rumors are pointing towards a June 13th codex release. Now we are getting more info that Space Marines will be the next set of releases, and will go over a 3 week release period.
Please remember that these are rumors
via Steve the Warboss on Faeit 212
-Space Marines next after Mechanicus.
-3 Week Release
Previous Space Marine Rumors
http://natfka.blogspot.com/2015/05/new-space-marines-codex-on-its-way-with.html