I am looking for this same thing. I propose that groups be implemented. It would work similarly to how the option for “admin only” can be applied, except that option would be replaced with “Available/Visible to Group” and then you would select which groups could see that dashboard. I suppose having a dropdown with checkboxes for individual users would also work though. I’m a Windows admin so groups is what is familiar, hah.
If I knew how to submit a feature request, I would.
Edit: Well that wasn’t too hard. Thanks Google. Here it is: