Well, three things.
Firstly I totally forgot about the RAM when I was tossing out my figures - so big big omission on my part.
Secondly I was actually thinking about the same Intel costs to fab when tossing out my estimates (max capping at $100 each, CPU and GPU). I don't include the R&D and all that, just the costs associated in the actual manufacturing in determining whether a console is 'profitable' to sell at a given price or not. With ATI's talk of 'fabulous yields' and the XeCPU being of a manageable size in today's terms, I would think it not too bad.
Thirdly, yeah the shipping, case, motherboard, DVD, etc etc... it all adds up, for certain. But to how much? I'm just thinking that at the end of the day, the components of the 360 can't come to too much over $300. I could be way off, I don't know. But I know I can buy cases, motherboards, cables etc etc and come in less that $100, so I imagine even with more exotic componentry, Microsoft will do well there.
So I totally agree that they are likely taking a loss on the hardware, I just don't think they're getting completely hosed though.
Again I factor out all non-direct costs though, so salaries, R&D, marketing, etc...