In Unity Connection the SA has some basic info about references when you go to delete something, but it's not what you'd call a report. There's also some stored procs that generate similiar information but taking that and kicking out a report isn't trivial. Global Subscriber Manager kicks out a report for references to a subscriber you're going to delete, but not call handlers and the report is the output after actually deleting the subscriber (i.e. so you know what changed automatically during the delete process).
I could probably add a read rough report (i.e. just a .TXT file output) to the Audio Text Manager tool that would let you pick any call handler or subscriber and run through and find all references to it and just list them out as it found them - it wouldn't be real pretty but it should be comprhensive. It'd be fairly easy to make it work for all 4.0(x) and later builds - 3.1(x) and earlier would be a bit more of a challange - what version of Unity are you at?
