[vansmith]

A lot of device support is built into the kernel. NIC drivers, for instance, are either built into the kernel or built as kernel modules. It is very possible therefore that support for the hardware on the Mac is not built into the kernel. There are some "exceptions" though, such as the GPU which can have support added afterwards. That said, the nvidia and ati drivers actually build kernel modules IIRC.

Upon some further reading, you may need to patch the kernel with some patches but depending on your hardware, you may be able to avoid this. Your best bet would be to provide a list of the hardware that doesn't work and the name and model of each piece so we can see what is and isn't supported.

As for the networking, can I assume you are using wireless? I only say that because ethernet NICs are pretty well supported and you should have no problems with them (in general). The only thing I can think of right now for wireless would be to install ndiswrapper and use the Windows driver for the chipset.