Ok, it took me few days but in the end I managed to do something.
I had to make it by myself because there's no Metro Window for Net Framework 3.5.
I combined some of the references below:
Launch window's System Menu on custom window
http://www.codeproject.com/Articles/107994/Taskbar-with-Window-Maximized-and-WindowState-to-N
http://blog.magnusmontin.net/2013/03/16/how-to-create-a-custom-window-in-wpf/
http://codekong.wordpress.com/2010/11/10/custom-window-style-and-accounting-for-the-taskbar/
Known problems / bugs:
1. When resizing the arrow cursor appear instead of the resizing cursor.
2. Designer cant display the custom window.
3. When maximizing, randomly there's blue (the color of the borders) in big area of the screen - for split second
If you can fix any of the problems above it will be even better but I am satisfied with what I achieved.
EDIT:
Updated to allow resize modes (also added sample)