We've just released a new version of our i3 interface application. It's moved forward quite a bit since version 1.0 and I'd say it is now 95% customisable!

New stuff for v1.2 includes:
Resizeable buttons, choice in text color, different screen resolutions as well as a custom sized one, speech feedback on the interface buttons and clock, no need to restart for changes to take effect, some overall graphical changes, a few bugs crushed and a lot of work on overall application reliability. Tested on Tiger (10.4.1).

We weren't able to add the iTunes interface yet due to serious reliability problems... but we're working on it for version 1.3.

Have a look:
http://www.i3team.com

No, it's not free... but it is FULLY functional as a Demo, so test away!