Well trust me it isn't likely to do it outside of a holiday week. DS, PS2, and Wii only accomplish these things in holiday months as well haha. Only other potential sales pusher is a thing like Slim or DSi that has increased sales at colossal rates but those kinds of things aren't likely to happen for PS3 again.
So things like GT5 release will definitely give push in sales but not enough to go over a million. Remember, PS3 is probably going to be at a 200k-300k sales rate a week in normal months when come off of holidays (which may be too higher but I think it is a good range for such a topic). Meaning you'd need something to expand sales by over 700,000 units. No game in the history of gaming has pushed that much hardware in one week. No matter how big GT5 ends up being pushing that much is not within reasonable range. I'm never one to cancel out possibilities so I won't here but we need to be realistic on that front.
Thus that limits our timeframe. Meaning it'll have to happen again on a Black Friday week or the sales peak of each year (last full week before Christmas). Even though ioi stated sales would be flat for this week, he's meaning on a day to day basis which means we'll still have to factor out the loss of hours on Christmas Eve and entire day lost of sales. Meaning there still is going to be a certain loss in sales (some even attributed to limited stock as usual at this time of the year). So flat is more or less saying drops won't be as large as they usually are due to the timeframe this year. 800k as someone stated for PS3 that week seems somewhat reasonable. Though it still has a shot but it'll need a big push in Japan, not flat sales to be able to achieve this.
Therefore we'll be looking to 2010 and we are left with 2 potential weeks. Hey it's possible but Sony is going to have to do some strong marketing and holiday pushes to really make it as big as they did this year. It's hard to come off a big holiday season one year and then outdo yourself the next year. Just ask Wii and 360. Hell ask PS2 and on a smaller level ask the DS. $200 PS3 would help but nothing certain yet.
Now one week I could suggest is a worldwide release of GT5 in the holiday season of 2010. That could certainly give it the boost it needed to be able to reach it. Might need some bundles to help it out as well.