I confess this is more a speculation than a rumor! But “something” made me suspicious. During my usual Sony patent search I found so many Sony patents that do explain the functionality of foveon like sensors. Unlike Bayer sensors the Foveon sensor uses an array of photosites, each of which consists of three vertically stacked photodiodes. The advantage is that you can have bigger pixels with greater light gathering ability, you have no color artifacts and no demosaicing is required. The drawback is that current sensors (from Sigma) are quite noisy.
Wild speculation: Sony keeps saying the A77 will be a revolutionary cameras. So what if the A77 has been delayed because Sony took time to develop a new 24 megapixel “Foveon” sensor? What do you think, is that something you would like to see in future cameras?