Miguel recently blogged about a trick for loading an executable assembly as a project inside MonoDevelop. I have now added native support for this feature, which means that it is now possible to directly open a .exe or .dll as a project, or add it to an existing solution. Also, MonoDevelop will get the list of source code files from the debug info of the assembly (when available). For example, this is what you get when you open gmcs.exe: