Sony knows what the demand is. They lose more money on the 80 gig than the 40 gig.
People are always throwing this out there, but I sincerely doubt it. The 40gb and 80gb are virtually the same hardware, but the 80gb sells for $100 more. Stuff like the card readers, extra USB slots, and Emotion Engine add up to diddly squat. Now, the 65nm chip versus the 90nm chip and the associated reductions in power and heating gear is a different story, but the only reason the 80gb units don't use it is because they're old stock. If Sony is moving back into mass-producing 80gbs, you can bet they'll use the cheapest, most modern process to do it.
This bundle might be slightly more complicated because they're including a 3rd-party rather than 1st-party game. I don't know what the cost difference on that is to Sony, but I find it hard to believe they're not making out better on the 80gb than the 40gb.