I'll look into this in the next few days.
If you subscribe to this thread, do you get replies? I have been.
Right now, there's only the one theme, so there's no theme changer.
There are a couple of reasons. The first is that it actually leads to decent text readability. This is right about the limit of line lengths before the lines are just _too long_ for people to handle, and you start having to do things like turning your head over the course of reading a single line. So it feels right to wrap things, rather than to let the lines go on forever and ever and ever...
I picked 1366 because it's a fairly common resolution for laptop screens. My feeling is if someone with a large monitor composes a thread for 1366, it'll look good for just about everyone. Where if they compose their thread for 2560, it'll start looking bad on smaller screens.