CrazzyMan stop it. You are wiser than that.
Your middle target, "optimistic", has 570K for just one week. Up 410K from average PS3 week!
Halo 3 didn't come anywhere near that. Despite selling 3.8 mill ww (900,000 copies in EU/others alone) the HW increase was just 80K (from 150K to 230K).
Yes, I know MGS4 comes bundled, but this game is a lot smaller than Halo 3. I predict 1.5 mill software WW, which normally would mean 30-40K extra HW, but thanks to the bundle & 80GB perhaps 100K extra HW --> 160K+40+100K=300K PS3s during MGS4 week.