Ahh.
OK.
Somehow the Project Settings in Vegas 11 defaulted to something other than the native settings of the video I was editing.
In Project Settings you can choose “match media” and tell it which media to match (I chose one of the videos I was editing) and it matches those settings.
Then when you “match project settings” in the “render as” dialog, it does smart rendering (so no data loss).
Now if I could just get that NewBlue Titler thing to work with my graphics card! 🙂