I'm going to set my expectations low for expo and say:
1) JJP will show images of game #3 but will not have a flipping prototype there.
2) Stern may show more information and images of BM66 but also will not have a flipping game there.
3) I think Heighway finished building their first production prototype a couple of weeks ago. I expect they will be working on a few issues and will not have approval from FOX yet, so they will be unable to show anything publically.
4) PPS/Churchill will reveal a prototype AFMr.
I hope I'm just being overly pessimistic, but if these four things come to pass, I think JJP will still create the most buzz with the reveal of Lawlor's machine.