This tool will recover a drawing and all of it's Xrefs then provide you with a report! It maintains the original file's format, Saves the original as a *.BAK, and updates custom objects if an object enabler is present.
I know I have asked drafter to "Follow the Cheese". Meaning Start at the top of the Xreference tree and fix every drawing along the way. Now we have something to do it for us.
It's probably not something that Autodesk is claiming as a enhanced feature of 2008 too loudly, but when you need it... it's awesome.