Custom Built Mac?

Hi there,
After a while of looking at Macs I have found that Macs don't exit.
I have found out that Mac:
Use other processors (Not made by apple)
Other DVD drives
Other everything!

These days I think Macs are the same as PC's, so I would like to build my own Mac with my own choice of DVD drive and processor in my own case (Would be a powermac G4 case!) I know that I can't just chuck any PC part it there, so how would I know what to put in there? Please could somebody help me where I should start - my cousin knows how to build a computer but he has only built ones that run on windows and linux. What parts would work if I wanted to run Mac OS X? I have heard of hakintosh, which I think is unreliable. Please could somebody help!

I should have the money to do this in 6 months.
Thanks,
John.


(p.s is this in the right section - I can't find a different one that will fit!)