No the black zephyr (HDMI and 120 GB HDD) is going to be a limited edition and for that reason and no other, the rumor is that it's only going to have a couple hundred thousand made. The zephyr will then go down to a normal price and become white because there will probably be enough people willing to pay $80 for a color.
I think during the same period that the zephyr is being sold, the premium version will also be sold still for $400 but yeah, you won't get a version with HDD under $400 for a while.
The main point is that the core is going to DIRECTLY compete with the Wii considering it's price (Nintendo's going to drop definitely still), Halo 3, and GTA 4. It's very posible that 360 will get NA.
MAF, shane kim has pretty much confirmed a zephyr and the other rumors are based on gamestop's own price drops.