EDIT: Well, I never thought to look at the pure melee version...d'oh. On the plus side, I got a crash course in XML.
I was looking for a way to get rid of the horizontal spell bar, but not lose the flow of the interconnected graphics. As a complete XML noob, I fumbled my way through it, and actually made something that worked.
Got the Combat Abilities moved onto the spell bar, which involved using Photoshop to adjust the image.
If any Hybrids don't like the horizontal spell bar, I suggest using the Pure Melee version, and just replace the EQUI_CastSpellWnd.xml file with whatever else you have. It's much easier.