After much sweat and tears, I've gotten the framework of the new UI system working! What you see below is similar to the original Main Menu, but it's now using the new UI system. I've removed the Options and dataset drop-down because those will be handled now by the launcher. I haven't gotten it to work with the rest of the game, so right now it's stuck on that screen alone. Once I get this screen to work with rest of the game, I will update the Desura recent build so you guys can give it a try.
It does process mouse events, you can see the "New Game" is highlighted because I'm hovering over it. When this is more fleshed out, this should help me progress quickly in terms of development. To a player, the changes isn't really noticeable aside from a slight boost in FPS (it's more efficient on top of being flexible!), but to a modder, it opens up modding approaches that previously required tweaking in-game code.