I spoke with my buddy that works for JD, he did a global search for the kit and found one dealer in the entire US that has 10 of them in stock. He said I might try calling them, but said they are probably going to be a premium on price or simply not sell them since they may be holding them for their use. He tried, but they said they weren't doing any dealer to dealer sales for them. John Deere simply hasn't produced enough of the parts or is having issues getting components to make them, as with a lot of manufacturers.
Other places I've found showing them in-stock online, but are in fact taking back-orders and submitting them to JD, which is an unknown ETA. I've had to cancel two orders that were showing in-stock, but indeed back-ordering.
I'm not sure the DIY route would be ideal since I need this kit to run/install the backhoe, and also want it to be under warranty.
Again, I do have work to do that doesn't need the backhoe, so getting the tractor back is the best direction for now.
Edit: I did follow up on the parts lead, it was a no-go, their inventory count was off and nothing was on the shelf at either of the locations I called.