ubuntu-recentquicklists
Finally, there are recent-files quicklists for Ubuntu, as Windows already has for quite some time. This script adds recent files (you can choose how many days old they might be) to the right-click on the unity-dash's launchers ("locked to launcher"-apps in taskbar, see screenshots "screenies").
Installation & Autorun: see https://github.com/thirschbuechler/ubuntu-recentquicklists/wiki/Installation
Huge thanks to https://forum.ubuntuusers.de/topic/libreoffice-unity-dynamische-quicklist/ (german post), which provided the framework to expand the functionality from being limited to libre-office to serve all applications. Also, stackexchange (in particular stackoverflow) helped a lot.