Id like to see this aswell, but even more "options", much like (hate to say it) WoW UI templates for addons.
Where players themselves could re-design the shape & overall visual layout of the UI's components.
Doubt this will ever happen but... i really hope, because i really REALLY like to paint / Design stuff like this.
I made a post about this some time ago, didnt seem to be very popular ; ;
Link:
http://forum.square-enix.com/ffxiv/t...-Layout-Addons
Here's just a preview of something fast i put together back then.
(For fun ofc, what could be)
Custom-made UI Layout.