While not inventory space per se, (Found it!)

All the jobs and classes will be getting new abilities along with new options for cross hotbar users to quickly toggle between pages to account for the new tricks. The team has also heard the requests for more armoury chest space, but due to the database structure of the game and the high number of per-character data, it’s not a simple solution to implement. Players will be getting access to more retainers to help address storage issues, but whether or not more armoury space can be added is still to be determined.
http://massivelyop.net/2015/03/07/pa...naoki-yoshida/