I can't be the only one that uses a Proclip for my devices in my vehicles.. So I reached out to @ProClipUSA via Twitter to see if they would be offering a mount for the KEYone, was asked to DM them to put my email on a list as they are "gathering emails to see if there is enough demand"..
I've been using Proclip mounts for many years, the last one I bought was for my Passport. I would be nice to have a KEYone mount, however I bet they will just recommend one of their adjustable ones - which are pretty good too.