The entire UI for orbiter can be changed beyond anything that XBMC can concieve.. but it does take a considerable amount of time investment, because you are essentially developing user interfaces not only for on-screen displays, but also for PDAs, tablets, cell phones, and other portable devices that can control a LinuxMCE system as well.
I will be posting a series of screencasts on using HA Designer, and hopefully this will encourage people to step forward and help us work on more UI possibilities.
-Thom