There really isn't anything to package up... You buy a regular/rectifier, and that's it. It's basic wiring other than that. I've seen batteries mounted in dozens of different places, so unless everyone agreed to mount a battery in the same spot, then a "kit" really can't exist. I mean, I could throw some wire, some shrink tubing, and some crimp ends in an envelope with a trailtech reg/rec, but my time is worth much more than it would cost you to buy the wire... lol
Not trying to sound like a dick, but nothing is really "plug n play" with a DC Conversion. People all have different harnesses with different things eliminated. Not to mention that a kit MUST include an already converted stator, which would have to be brand new to avoid liability issues, and then at that cost, it would be astronomical. No one would buy them.