Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux. Xonotic is a direct successor of the Nexuiz Project. The project is geared towards providing addictive arena shooter gameplay which is all spawned and driven by the community itself. Xonotic is a direct successor of the Nexuiz project with years of development between them, and it aims to become the best possible open-source FPS (first-person-shooter) of its kind. New trailer coming soon Please post all support issues in the forums for the game.
Here's me toying around with the panelhud system from the fruitiex/newpanelhud branch in Xonotic git. As you can see the HUD is organized into "panels", each freely movable and resizeable. Their backgrounds can also be configured, as well as the content to some degree. The system already supports different skins, which I couldn't yet demo as I only have one skin (the old HUD :P), plus some extra backgrounds/borders that I quickly created. By drawing a dock background and setting the panel backgrounds invisible, one can customize it even further, for instance to look almost identical to the old HUD.