Conversation Window (good news):
You can currently change the background of the conversation window as you normally would, however a black area remains at the top. I'll try to fix that up.
And colorize works just like normal.
Contact List (bad news):
I have no idea how Wave11 has its colors implemented ( i haven't looked at any code), but it appears to me that its done using horizontal gradients. My guess is that based on what you select in the installer, it changes the corresponding lines to hold those color values.
All I can say is, it would be POSSIBLE to add that option for parts of my skin (probably only the background colors), but I have no idea how to do so. It would also be much more work, seeing as i dont use rgb values as heavily.