PortableApps.com has released a portable package of MyPaint 1.2.0 for use on USB drives, cloud drives, and locally without needing to install with admin rights. The launcher that assists the app and the installer it is packaged in are open source under the GPL as all our utilities are.
The launch announcement is here: http://portableapps.com/news/2016-08-12--mypaint-portable-1.2.0-released
The app page is here: http://portableapps.com/apps/graphics_pictures/mypaint-portable
Any questions or suggestions are always welcome.
And if someone has a better representative image I can use, please send it my way so I can update the screenshot. I made a quick one demonstrating some various brushes just for the release.