First week sales for FFXII will be 1.5 million, and it will push and additional 100-200k consoles.

2.5M-3M first week.
300-400k HW.

Once again Crazzyman out does himself =P

I'd say 1.2M first week with 200k hardware. Usually I would predict lower given how poorly some PS3 exclusives have done on early sales but in Japan games have had larger impact than I expected (HSG5 being the main one) so I expect Japan to follow traditional trends more closely than I expect either Europe or America.

 I think 1-2 million is indeed possible considering the only RPG series that is more popular than Final Fantasy in Japan is Dragon Quest.  Many core games don't sell is for varying reasons.  For example, No More heroes didn't sell mostly because the game for too unconventinal for the Japanese and none of Suda 51's games never sold particually well.  I think everyone else knows the other reasons.

 Not quite true, even DQ is only second as far as Japanese RPGs go. Pokemon>DQ>FF.

 I don't count Pokemon partially because it is not aimed at the same audience as DQ or FF

It will do very well and move a lot of hardware. I'd say close to 2 million first week, maybe 1.8.
Lifetime sales in Japan are hard to predict, but well beyond 3 million I'm sure, maybe as much as 4.5.

Why do people keep claiming that it'sgoing to perform as well as FFXII with a fraction of the install base?

 The PS barely had 8.5 million users when FFVII launched, yet that game did nearly 10 million LT sales and topped 2 million first week in Japan alone. FFXII is noted with just a little over half of FFVII's sales.

FFXIII is the series debut on a new platform, much like FFVII and is easily the most anticipated title for the PS3. Even new franchises on the PS3 with a little over 9 million users have 2-3 million sales some of them, so to assume that the most anticipated title will sell this well makes sense to most people.

And besides; a commonly used argument in here is that everyone who wants MGS, FF or GT allready own a PS3, so there's 9.44 million potential buyers... j/k

But still; you don't want anything good to happen to Sony, do you? Be a bit more subtle, it's getting old.

Tough question really, I'll get back to you on it by the end of this year... right now there so many unclear factors that its hard to actually make a decent prediction.