Considering how much we nit-pick about the noise of the SX600-G and SX500-LG, they're probably taking their time to make sure it's solid, at least that's my hope.
I talked to Tony a few days ago and the SX700-LPT production was pushed back a few weeks due to a part delay. I'm not sure how long it will take until we see units in stock at retailers though.
Several months is my guess. First batch probably takes month to produce, then they are going on shipping boats to US and Europe, which takes another month.