Sony is roughly breaking even on every PS3 sold once you take in everything to consideration: manufacturing cost, shipping, retailer incentives, ect.
However, it's a lie to think that the Arcade is not making money, when it most likely was when the price dropped to $199. Microsoft has made a profit in their gaming division for the past year+ straight, and Sony has posted a loss just about every time. That tells me that one system is profitable, and the other is certainly not.
Back from the dead, I'm afraid.