Ok one step further, but I seriously don't see how this could work.
You can gain access to the new custom file by doing the following in a user control:
So we could potentially add methods to that class to change the title, but it won't work, because the SetTitle method is being called very early on in the page life cycle... before the Page_Load of the User Control.
So the question remains: I don't see how this custom control would allow you to change the title of the page at runtime. This must be possible though since the Blog and News modules manage to do it?