I have had a look at your OneAdmin Tutorial on youtube Cannot get it to work even tough I'm admin to I do not have the correct credentials to access the plugin.
How ever I was looking at this template at http://startbootstrap.com/template-overviews/sb-admin/
and this got me thinking. I have the events calendar, Event Booking Calendar and PHP News Script for a club website. There are a number of club members that update the website. They have set rolls to play some member deal with the event calendar and not bookings or both like wise the same with the news.
I would like to have one administration system where the user logs in can read internal messages.
access there permitted section eg events booking calendar and News.
Administration can in one place define the user permissions for each of you package

Just a thought as that is what I would like to do on the site Im working on