Frank has been working on a planetary tuners with 10:1 gearing. Have they been manufactured yet? I am working on a guitar that needs them, or something them.
They are not planetary, but cycloidal reduction drive, and they ARE available right now.
You can get them from Rickard Banjos in Canada: https://rickardbanjos.com
I did the preliminary development and turned the project over to Bill, who ran with it, improved the tuners and got them into production.
You can also get them on the Gryphon web site: Cycloidal tuners at Gryphon
Because sets could be 4, 6, or other numbers for different instruments, they're priced as individuals. Response has been universally positive!