This is hard. I mean, it's a whole bunch of skillsets and I can totally see how there are people who are really really good at designing this sort of thing, and if anybody ever tells you that "art" is superior to mere "design," call me and I will come and kick them in the shins, because I am an artist and this makes my brain hurt.
So I spent the weekend playing horrible brain games like "How do I make a UI that looks soft and fuzzy and sewn together?" and "how do I fit this stuff here?" and "How exactly does one make a floppy disk icon look soft and fuzzy, anyway?" and anyway this is where I am so far. (I will show no one the UI for some time, because I anticipate much fiddling and perhaps sobbing.)
I still don't promise a time frame, but stuff is coming along at a good clip, probably because I am so miserably busy on so many other projects that working on this feels very much like getting away with something.
(Also, if anybody has links to, like, game design interface tutorials, I would LOVE LOVE LOVE to see them.)