I agree that 24 has become the sweet spot and most likely Fuji will get there. As to if it will be full frame or APS-C is the question. Most 24MP sensors I have used in APS-C just get too much noise by 800 ISO. If Fuji goes full frame 35mm then they will also have to come out with a new line up if lenses just like Sonys FE line.
Fuji rumors has written several blurbs about a possible full frame fixed lens like the Sony RX1 coming later this year around Photokina.