Rumor, conjecture, flimflam. The internet is full of it and as a rule Co-Optimus tries to rise above; unless it mentions a sequel to the top LittleBigPlanet series. Few games on the PS3 were able to combine fun and imagination better than this 4 player co-op platformer. Sheffield (that's in Britain) based developers Sumo Digital are said to be creating the latest Sackboy adventure.
With Media Molecule turning their attention towards Tearaway, it is unlikely that they would be involved directly in a new game in the LBP franchise. It makes perfect sense that Sumo are rumored to be developing the next game, as they already have experience designing the cross patch that allowed the Vita to be used as a controller.
VG247 do not state who their source is, but with development on the third outing reportedly being going on for a year, it seems like a likely bet it will happen. Rumors are rumors, so should be taken with a pinch of the salty stuff, but this does not stop us imagining what LittleBigPlanet 3 may hold and opening up a community question!
What would you like to see from a third LittleBigPlanet?
Personally, I think the timing suggests that the game may be planned for the PS4 launch window. Could Sony be looking to take on the Skylanders crown and develop a peripheral that reads Sackboy toys?