WHERE TO GET A COMPLETE Wire HARNESS?

I went through the same headache, and the options are few, and they suck.
I ended up buying large spools of wire in different colors, different connectors, etc, and using the wiring diagrams I replaced what was damaged, too short from years of hacking, etc. And I kept to my goal of using little to no electrical tape.
Keep the plastic connectors to use over, and you can get the metal connectors for those and the bulkhead on-line or at a good parts store.
Then I bought some different sizes of the asphalt covered wire loom, and the large size of electrical tape to wrap some sections, the same as what was there, and it looks like new.
I replaced all of the bulbs, cleaned the lenses, fixed the grounds and added a few, and everything works great.
It was my dash harness and the rear harness that were the issues. I left them plugged in one area and laid them out of the car on the front lawn and went to work. It took a full day, but it was well worth it and I spent less than $100 for all the stuff.

Another idea that I got from looking at the aftermarket distributor I bought, is the connector on the distributor is a new style waterproof connector, with 3 wires on each side. I have a new trailer hitch wire connector kit in my toolbox that has a similar connector with the wires. I did not use it, but if I ever needed such a connection it is a good alternative - and cheap.

Hope this helps.