Long time ago I wrote how to create a (blank) Visual Studio solution from an add-in, which while not very useful, it was tricky:

HOWTO: Create a solution from a Visual Studio add-in.
http://www.mztools.com/articles/2011/MZ2011001.aspx

Today I have written the continuation with something more useful (specially if you practice integration testing), how to create a project:

HOWTO: Create a project from a Visual Studio add-in
http://www.mztools.com/articles/2013/MZ2013022.aspx