Thanks for creating this blog and sharing it with the community. It's worth mentioning that we've made a lot of changes to the header bar (that you can see in the latest Community source but are not yet in any official release). Although we will continue to support this style of header configuration, we're actually moving to a different model which allows a lot more flexibility in adding, modifying and removing elements in the header. One of the current problems with the header config is that it is not easy to remove elements and it's also not possible for multiple (separate) extensions to be applied to the header.
This blog though is still applicable and very useful for Alfresco versions 3.4 through 4.1 (as well as the 4.2c community release).
