Oh, that is
nice. I can immediately imagine how it's supposed to behave, even before reading your text description. Keeps all the information right there, gives obvious mouse-navigation, and it keeps the impressive swishing-and-zooming of the constellations.
Pair this with an input overhaul for the in-constellation navigation (movement locked to the connecting lines), and it would be perfect.
...A UI mockup should not make me feel this much joy. It's a sign of how bad the existing UI is that just the
thought of using this instead gives me a warm, happy feeling deep in my chest.

Aside, this should totally be possible. Because the UI is coded in Flash it's a pain to reverse-engineer, but it does mean that we can create entirely arbitrary modifications or even entirely new menu interface designs. The only limitations are what data the underlying game engine exposes for use in the Flash menus, and which Flash files the keybindings are hardcoded to bring up (e.g., magic versus inventory menus). However, the SKSE ("script extender") will eventually be able to expose more data to the UI and be able to change how keybindings are mapped to menus. In the end, we should be able to
entirely dispose of the existing interface if modders want to go that route. The existing system is going to be a pain to start modding, but once we get the technical knowledge to do it, the sky's the limit!
Ha, thanks! See my worry is that something I knocked up in an hour on photoshop while searching for the right font and occasionally going to get my sick girlfriend a lemsip shouldn't really impress
anyone more than the design department of a company who's PC game is outselling Modern Warfare 3! More on-topic though, yeah I think the movement lock would be a bit better, although even just locking it to that constellation would be fine, as my real gripe is I'm trying to level lockpick and suddenly find myself on light armor or something. I think the problem is they were trying something like Mass Effect's galaxy map, but in the wrong context, and it ended up more like the 3D sphere grid thing on FFXIII.
It's good to know UI mods will be possible though, I'd be quite happy to contribute to one if anyone knows their Flash - I'm going to be covering it this year at uni and I have some game scripting and graphic design experience, but for now I wouldn't know where to start. Maybe if there's a way some of us with ideas could send them to the guys working on major UI overhauls they could implement the ones they thought were good.
Also, there's something out here that fixes some of the issues apparently - http://www.skyrimnexus.com/downloads/file.php?id=88
And OMFG.. 360 hotkey enabler. This will be awesome if it works with the tiny keyboard you plug into the 360 controller, even better if there's one that enables the whole thing (we can but hope) - http://www.skyrimnexus.com/downloads/file.php?id=310