It's rare to read a lot about coming point and shoot cameras, unless there's a G series on the horizon.
I do however see the following cameras getting updates:
PowerShot SD1000 -> SD2000, i can see it getting IS and more MP.
PowerShot A570IS -> A580IS, it sells very well, more MP.
PowerShot A560 -> I'm not sure Canon keeps this around, I believe they need to have IS in all their compacts. The only other difference from the 570IS was it not having manual controls (P, AV, TV, M).
PowerShot TX1 -> TX2, I have no experience with this camera, but it does have some fans. There are obvious shortcomings that could be improved.
I don't see any ELPH cameras that might be replaced.
I could also see a compact announced to compete with Panasonic's high FPS DMC-LX2K. I don't think we`ll see a 60fps camera to compete with Casio.
I don`t see any Canon compacts appearing with CMOS sensors until the G gets an update.
As for HD video, any TX update will have it. Doubtful any other model will yet.