Well, GM pulled through for me, they were able to locate the regulator out of dealer in KY and got it to me today, and it works great!
It cost 145 with tax.
Gregory, your write up made things go smoothly, very much appreciated. There were a couple of things different, so I'll copy what you wrote and edit it so if anyone else gets this, they'll have the step by step.
How to fix this problem
Remove the panel piece inside the tailgate, 6 torx bolts.
Remove the black 'computer' by disconnecting the two plugs and three bolts.
Remove the black metal piece, several larger gray bolts.
Look inside the tailgate, and there are two black round pieces that control the door hinges. On each one, there are small metal tabs, push both towards the sky simultaneously. *Be careful of sharp metal* Make sure someone else is there to pull the door once you hit the manual releases, or the door will shut back on you. Put something in the hinges to make sure it doesn't close on you.
Remove the rubber window squeegee seal on the top of the gate, (number 4 from the diagram). Two torx bolts on the ends of the tailgate must be removed first. The brake light and wiper arm can stay in.
Disconnect 2 heater wires (Purple spiral cords).
Unbolt the window from the regulator carrier, and pull the window out the top.
Under the round rubber plugs there are two bolts for the regulator guides (rails) and two at the top of the door. take the bolts off, and the bolt holding the actuator motor.
Remove the braces from their keyhole mounts, then collapse the whole mess and work it out through the openings.
Remove the actuator (Motor, electrically connected) from the regulator, via three bolts.
Take replacement regulator and re-attach the actuator, and feed in the same way to took it out. Reverse steps to get it back in.
There is a chance adjustments will need to be made to get the glass to fit right.
Once everything is in, you will actually need to do what the car says and consult the manual to reset the window.
Do this by rolling it up until it closes, and hold for two second after it closes. Then roll it all the way down and hold for two seconds.
I had to do it a couple times, but i finally got it.
Unfortunately, to do this step, you have to close the tailgate, so if you didn't get everything right, you have to reopen that tailgate manually, or finish up inside the truck.
If you're reading this because it happened to you, good luck finding the parts! Don't be intimidated by this repair. It looks daunting, but if you can get good replacement parts, and an extra hand for getting the tailgate open, it's not bad at all.
Thanks again for the help guys!