[Q] Theming Lollipop Notification Background

In Lollipop (5.1.1) I am wondering if it's possible to change the Notification Background to an outline, rather than the solid white it is by default. I know by using CM's Theme Manager you can change the shape, colour and transparency of this, but I want to the change it to an outline with no fill, or if not, something like this: http://tapatalk.imageshack.com/v2/15...b576725372.jpg, with just lines.