Maybe we will see this in Piwik one day soon?
Measuring Performance with Google Analytics Site Speed Reports
http://youtu.be/NCFVEuKQgBM?hd=1
Thank you for all your work. 
Yes you will, in a few months See feature request: Propose Page speed reports, Load time analytics · Issue #1700 · matomo-org/matomo · GitHub
Happy to see that you guys have been planning/working to get this done from a long time ago already.
Thank you, Matt.