Yeah, nothing solid as you say but iirc there's 3 proposed routes for Oxford to Cambridge rail around Sandy, a couple of dual carriage options for the 428 to hit the Black Cat roundabout and a couple of A1 options (east and west) on top of just fixing the current route. Once these are known they're planning to stick houses on / around and it's in that general area. Likely to be a new station on the North South and East West rail crossing too if it isn't somehow built into Sandy (unlikely given current infrastructure and the hills immediately behind). Central Beds have just made their initial proposals based on what they think is likely / want to happen. They don't really have a clue (this was obvious when I went to the consultation). It will probably make things interesting for a decade or so once they start though.