I think they are clearing their stock of 80 gigs right now because sony is banking on the mgs4 bundle being the consoles "savior" essentially. Nothing wrong with that.

I'm not even bother to discuss sale increase or not.
senario 1 : introduce 80 gig with bc for $100 more or the same price
this going to piss off all those bought the 40 gig without bc , remember sony's reason to cut out the 80gig was so they can put more focus on the ps3 brand. I love to see how sony going to spin this around by rereleasing the 80gig with bc.
senario 2: introduce 80 gig without bc for 100 or more
This gotta biggest bullshit sony can put up with, I can get a much bigger drive with $100 + the old existing 40 gig one. Only a fool will go for this deal
senario 3: Introduce 80 gig without bc for the same or lower price to replace the 40gig cpu.
This seem like the most disirable senario for a win win situation, a smart move by sony instead of a price cut of the 40gig model. The price difference between a 40gig and 80gig is only few dollars, and this will appeal more to the consumer, but the negative impact is the 40gig will not sell if sony release the 80gig for the same price.

One thing is that the 80 gb is already pretty much gone from retail shelves.

They will be a 3-4 weeks spike of people waiting to get 80gb/MGS4, then fall back to more normal levels.