Over at ARCxl, you can download a bunch of Revit details for free. According to the website, these details were all created natively in Revit.
Effective July 19, 2011, two very significant alterations were made to the ARCxl website. We have added CAD/dwg, and PDF file formats to our library. We have also removed restrictions on account location and email address types.
Upon downloading a detail, you must also agree with this popup: