Rick made his harnesses one at a time, when someone wanted one. He used parts similar to what you are suggesting, in his opinion only the best parts. It was truly a plug in system! No electrical experience and you could do it anyway.
I would encourage you to put a picture of one in the homegrown for sale section, at a "more" reasonable price than some of the ones you were told about and see if there is interest. If I hadn't done both of Rick's harnesses I would be.
He also did a great tailgate window harness. We rebuilt the stock Jeep switch for RT so the tailgate switch looks stock as it sits in the dash, but works like the newer rocker switch that he used. Really simple switch rebuild. His harness came with the newer rocker switch which is what I'd recommend. If someone wants the old switch, just rebuild it to work.
79 Cherokee S (current project)
82 Cherokee (parts for the 79)
Member FSJ Prissy Restoration Association