I figured out what the issue is. I have both VS2008 and VS2005 on my machine. When I opened my VS2005 the object mapper was there. When I opened my VS2008 the object mapper was missing.
The documentation lists IdeaBlade.DevTools.Orm.AddIn as the file to rename. You have to rename BOTH the dll and the addin files in that directory, not just 1. If you have VS2008 then you have to rename the IdeaBlade.DevTools.Orm.VS2008.AddIn file as well.
It's pretty obvious but I followed the documentation to the letter with no interpretation and that's why it didn't work for me the first time.