So, this is just some playing around in Photoshop atm, but I think I like it... Don't know if I like it enough to try coding it, but anyway:
The idea was, to make sort of a steampunk-inspired UI... With this strict layout I'm limiting myself to 24 visible buttons, but I really like the look of this.
You can see portrait (left) and minimap (right), an XP-bar (bottom) and the players health and powerbars (top).
What do you think? It is worth digging some further on this idea?