Is it possible to use a contorted icon as a progress- or scrollbar in a Gtk 3 theme?

[raphaell2]

Years ago, I was a lot into Puppy Linux for a while. At the time, Puppy had a Gtk 2 theme they called Stardust that, instead of simply setting a colour for scrollbars and progress bars, used little icons and told the software to "stretch" them into shape to form scrollbars and progress bars. I really loved the "shiny" effect that this had when used with the right icons. I'd love to be able to install a Gtk 3 theme that does the same. Unfortunately, I know basically nothing about making themes. Here are the icons in question: button1.pngbutton2.pngspin1.pngspin2.png

Any ideas?