I just watched an online event put on by DIME and asked Eileen Roche directly, "will you ever make a hoop for the Janome 15000 machine?"
The answer is NO. She explained that the connection point of the machine would just make the hoop too heavy for good performance.
I had a feeling that would be the problem and the answer.
In lieu of that my husband made me a really nice version using some of the ideas that Jim & Diane had done. So, I'm happy.