I've tried to figure out whether its possible to scroll files (tab) in Amarok up/down (vertically) instead of sideways (horizontally). Just like you do when scrolling the collection (tab). I haven't found a setting within Amarok so I'm not sure where to look.

I'm running KDE on one computer and XFCE on the other. Help is much appreciated.

You can try to change to Detailed view and see if you like it. It's the seventh button from the left here (in the Files toolbar).