currently there is no option for adding a reference geometry in the drawing view background.
it is frequently used in the large assembles with background geometry as a reference drawing without linking with model (parametric ) as like sketch's with phantom line .
this feature is already available in the other 3d software's.
if we had this feature in inventor it helps lot those who are working with larger assemblies.
working principle: by browsing model tree in the drawing sheet , select the sub assemble or part and convert it as sketches or make a particular part /assembly in to a reference geometry by converting it and break the link from 3d to 2d( after converting there is no link(parametric) between drawing and model for the converted sketch's)