Apple designs the motherboards and then Foxconn makes them using standard components. Apple does not like adding extra bits on top of what the Intel chipset provides, hence why we don't have support for things eSATA and USB 3. There are obviously a couple of other bits and bobs, like the wifi chip, but I am not sure who makes these. I suppose you could check out one of the disassembly sites - they usually list a lot of this info or study the diagrams and google the model numbers on the bits that you can see.