I think I'm finally finished hacking on the Navigation History feature in MonoDevelop, which started off as more-or-less a direct rip-off of the one in SharpDevelop, but quickly began incorporating improvement ideas from Miguel, Lluis, and myself.
Now on to bigger and more exciting things... namely, refactory features.
A few weeks ago I had taken a look at some of Microsoft's Visual Studio 2005's and SharpDevelop's context-menu-based refactoring functions and have just stubbed a few of them out in current MonoDevelop svn (added the Rename and Implement Interface items):
In the above screenshot, you can see the menu we get when right-clicking on the name of an interface in a class definition.
Here, I right-clicked on the name of the class in the class definition.
Going forward, I'll be looking at the refactoring functionality that Eclipse provides along with Intellij's, ReSharper's and Refactor Pro's features.
So far I've really only had time to watch the Refactor Pro demos. They are pretty awesome, but I think the UI bits (at least) are a bit over the top. Certainly not going to be easy to implement. I'll probably be looking at easier approaches.