If you ever wanted to replace the GtkHTML-Editor of evolution bz something different, you should take a look at Bug 221974 (allow user to choose editor component in mail settings).
This has originally been for using vim as the editor component in the mailer. But I think it should make using GtkMozEdit easier too (which is something that many people are waiting for). Dear Evolution Team, please tell Jason that his patch will make it into 2.8 and he'll do all the work (except the commit, of course).
