It's really looking like the XBox One is going to be the system of choice for scalpers and flippers. Sony is going to be intentionally throttling their supply and releasing the PS4 in a much more measured manner. Instead of flooding stores with an initial shipment and then supplying as quickly as they can, they are going to keep more reasonable, steady flow over the course of the holidays. This is going to force potential scalpers to line up regularly in order to artificially throttle supply.
Of course, if demand is high enough, the system will be hard-to-find anyway. But it will be much harder for flippers to enjoy a quick, launch-related turnaround. It might be a better idea to limit initial flipping purchases and wait to see how the market goes, or focus on international flipping. (those Japanese aren't getting their PS4s till February)
Since Microsoft is going with a more typical shipping schedule, their system is going to be more attractive for flipping. There is also the rarity of the Day One promotional units they are going to be distributing. Those will actually have collector's value, and could go for above retail on that factor alone. There is also the advantage of the PS4 launching a week earlier. Flippers focused on the XBox One will have a weeks head-start to see how the PS4 performs. (and test the waters as far as next-gen demand goes)
On the whole, "flip or not to flip" argument. I don't think flipping is inherently evil. Especially for a mass-market device such as these home consoles. There are going to be tons of these things available eventually. Early flipping on launch window demand is no big deal.
My personal policy is that I don't flip for peanuts. If I can only expect to get 10-20% over MSRP for a system, I'm not going to sell it. I picked up a Wii U at launch, and left it alone for a day or so to see where the demand might be. Once it was clear that they wouldn't be flipping for a high markup, I cracked that baby open and started playing.
I might get caught up in the launch excitement, and take a similar approach to the PS4 and XBox One. The fact of the matter is, my time is valuable. I have a steady job, and make a decent hourly wage. The kind of profit I would make off of flipping one of these things is going to have to be substantial if it requires me to stand in line for hours.