How to change the look of launcher buttons in DockbarX?

The look of the launcher overlay is controlled by your active theme (found in the appearance tabof DockbarX's properties). To change it, first check that thefolder ~/.dockbar/themes exists (and if not, create it), then copy your active theme (a .tar.gz file) from /usr/share/dockbar/themes/ to ~/.dockbar/themes.

Once you have done this, open the theme and find the pixmaps folder. You can then swap the button.pnbg and launcherbutton.png files for anything you like.