Qt 4.3 Style Sheets, as you most likely know, introduces styling of most widgets. The documentation is a quite silent when it comes to providing "style templates" - templates that you can just copy/paste and get started with styling the widget. Today, I started creating templates for QProgressBar and QScrollBar. All this will become a part of 4.3.1 Style Sheet documentation.
For vertical scroll bars, you will need to replace width with height and use up-arrow and down-arrow. That said, remove those boring borders, slap in a few border-images, gradients and background color and it's simple to create beautiful custom scroll bars.