Boston 2024 just posted these highly generic renderings on Facebook. There's nothing that even links them to Boston. These renderings could be the bid for LA, SF, DC.
FWIW, BBJ has captions on these images now - they actually asked someone from Boston 2024 what they were supposed to be:
"Olympic Boulevard", presumably with South Station to the right and Fort Point Channel to the left. I doubt the artist's sense of scale is so far off that both sides of the channel are shown, so the concept is likely that amenities are floating on barges in the middle. It's an interesting idea. I'm not really sure what the "5" on the sign means, but maybe those barges are lounges that people can buy their way into?
"International Plaza at the Athletes Village." Everything in this picture would be new construction on the Bayside Expo site. I'm not sure if the First Night parade is suggested as a regular occurrence a la Disney World, or whether it is assumed that athletes will carry large cloth birds with them as they carry out daily errands. Since the rendering does not appear to show a planned event and several of the pedestrians are viewing the action quizzically, I suspect the latter.
"Another view of the International Plaza at the Athletes Village". This is the only one we could all place, and it's indeed from the Bayside Expo site. I like the idea of designing gathering spaces that overlook the water into the Village, particularly if it has a future as a dormitory quad. It could give UMass a nice selling point.
"The Boston 2024 Aquatics Center." This picture is set somewhere at Beacon Park, though it has no existing reference points (EDIT: that could be Harvard Stadium in the background, but it isn't visible from the rail yard). I'd guess that since Boston 2024 knows that Tufts is in the pipeline, they haven't given much thought to where exactly the Aquatics Center would go in the MassDOT site plan, so this picture is complete fiction.
BBJ source:
http://www.bizjournals.com/boston/g.../01/first-look-renderings-of-boston-2024.html