I'm sure that y'all (it's a Southern thing) have heard about Painless Performance before, but just in case you haven't, maybe check them out for a custom made wiring harness for your individual application, or start with one of their basic kits and go from there. http://www.painlessperformance.com/
Of course maybe you're both just a glutton for punishment and want to do your own wiring harness from scratch one wire at a time. Just thinking about that makes my head hurt.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless