Stop with this "Apple locks everything down while everybody else is open" BS!!!!!! What you call "locking everything down" is building an integrated system. Microsoft licenses Windows to everyone and develops Office for other platforms besides Windows because it helps them make money. If they found they could make more money by writing Office only for Windows, they'd do it.
With that said, I think Apple would be utterly stupid to buy AMD. I fail to see what AMD could give them that buying from Intel doesn't. The only purpose it would serve is that Apple would not have to depend on Intel to supply chips, but that's not worth $5 billion.
Cute, but you are clearly blinded by the fanboy in you. Apple can gain several things from AMD. A good example is their GPU line and engineers.
Apple will lock down future AMD designs to work on Macs only. Obviously they might sell some GPUs, but at a higher price. But overall, it'd be a bad situation as only Intel and nVidia will be left for the market. Apple doesn't cater to low ends. (iPhone being the first)