Can't think of any OOB features to do this at the moment, but off of the top of my head, here is how I would go about it.
Develop a timer job to traverse your site content, going through each and every object, checking for references to each of the assets' unique IDs. I would then store that reference in a list specifically made for this data. Now, it's as simple as manipulating the list through either custom views or maybe something code-based to be able to display/work with the data how you want.
This would obviously not be real-time, but it would basically mimic a very rudimentary indexing functionality and shouldn't be too complicated if you are familiar with the object model from a coding standpoint.