I think You can use this:
Microsoft.VisualStudio.CommandBars.CommandBar menuBarCommandBar =
((Microsoft.VisualStudio.CommandBars.CommandBars)_applicationObject.CommandBars)["MenuBar"];
CommandBarPopup myNewPopUpControl =
menuBarCommandBar.Controls.Add(MsoControlType.msoControlPopup) as CommandBarPopup;
myNewPopUpControl.Caption = "MyMenu";
myNewPopUpControl.Visible = true;
First line is from the OnConnection of the Add-In template. As I experienced each element of Controls collection has a zero Id, so the arrangment might be problematic. Also you can create Buttons and PopUps with Automation (Exception will be thrown otherwise)
http://msdn.microsoft.com/en-us/library/microsoft.visualstudio.commandbars.commandbarcontrols.add.aspx http://msdn.microsoft.com/en-us/library/office/aa190793(v=office.10).aspx
Update: Your question seems to be a duplicate [a question] Adding a Menu to the Visual Studio Menu Bar within an Add-In [a]