this UI scales wonderfully to 1440x900, just have to do a very easy move of the UI components. Only have to do it one time, and then with your other characters, /load_uisettings and load the interface you customized
I found that one of the default screen UI layouts auto configured itself to my screen width of 1440x900, i just had to do a tiny bit of moving the chat window. (and customizing where I wanted things for the way I play)
Hope that helps