I am the author of the now defunct Sewell UI - after a long sabbaticle from the game, I found myself drawn back to it. Sewell is now a retired mote farmer, but I have been decking out Chamoise and leveling a Disc Priest, Cardinale on Undermine.
During my (long) break from the game, I played a lot of other games - one of which was Heroes of Newerth. I really loved the way that they put that together and decided that it would translate well to WoW. What you see is basically a conglomerate of existing HoN features, fan site kit and my own custom photoshopping in an interface that I really enjoy.
Probably the first thing you will notice is a lack of a huge matrix of buttons. For the doubters, bear with me. I tried to drill down on each of my characters, how many buttons do I frequently use. Why do I have a crafting button visible at all times when I may craft once every 3 days? Why are there healing buttons here when I use clique/grid? Then I classified what I needed to track and how.
I put my big ticket CDs on the 4 prominent middle spaces, basic offensive, heavy-use goes left of center, panic and other essentials went right of center, and then I created 6 additional buttons for mount, potion spillover buttons. I do have a mouse-over only button bar that I can put quest or macro deals on the far right as well. But If I use it a couple times in the course of a week, I don't want to see it all the time.