I'm currently performing a mode where I put a mac mini inside an NES, and so far have been able to remove the board, and gut the case to fit the mac mini neatly inside, using the NES cartridge port to accesss the Drive.
My problem Now is that I want to keep the NES looking almost exactly the same from the outside, which means using the original power button to turn the mini on and off.
Does anyone know if it would be possible to hotwire the power button in and use it to put the mac mini in/out of sleep?
http://www.appletalk.com.au/articles/miniserver/ If you want, you could even swap out the slow/expensive laptop drives and replace them with real desktop drives. The issue here is that you might need to build a few devices to power them (since desktop drives use more power). I suggest a few linear regulators, wired to supply the 12v and 5v lines. Should be pretty easy to swing if you're good with electronics (and if you aren't, look up the 7805 and 7812 regulators).
I don't know of many more helpful sites, but I'm sure there are some people here much more skilled in electronics than I am.