Using the "Find" tab I found.. (links aren't doing what I want today.. sorry).
(1920x1080) MurbUI 3.2 (3.2)
Renya UI ( 1920x1080 ) (3.2)
Boda's Black Box UI (1920x1080) (3.2)
Ultimate Shaman UI - 1920 x 1080 [WIDE] 16:9 (3.2)
Phails Hunter UI - 1920x1080 (Wide) (3.2)
Toodels Warlock RaidingUi [Raiders Choice!] [1920x1080 - Widescreen] (3.2)
SlaghornUI v2 [1920x1080] (3.2)
MI's UI (1920x1080) (3.2)
Pyskato's Restoration Shaman UI (1920x1080) (3.2)
Couture UI (1920x1080) (3.2)
There's also other UIs such as nUI (click my sig) that auto configure to any res. If none are 'what you're looking for', then give a little more description
.
Also, if you don't mind a little configuration on your own, most widescreen UIs should be 'close enough' to not need major repair (moving a few elements, adjusting scale.. etc.).
Good luck, hope you find something worthwhile.