there hase been this
also called 'unlimited expansion by us and the players'
When someone broadcasts content, Stardock moderators rate and define it more closely. From this screen, players can decide what types of creatures they want, the quality of the submission desired (we will rate the broadcasts in terms of production values as well), etc. These creatures will have associated technologies that are attached to them that are required.
it isn't anything particulary specific, but it does imply that this is much more than selecting clip together blocks seen in GalCiv. Obviously this requires custom models, custom techs, and similar features. They talk about how its like a game mod, but 'one step further' in company support. if they are considering this part of the game's ambition, I would say they are telling us that it WILL be part of the main game, i.e. will be available before release.