Is there a utility out there that will read all an ESP and tell you all the resources it references? Bonus if it identifies them as being in the data folder, in a bsa (naturally it would only look in the Oblivion BSAs, SI BSAs if present, and BSAs that match the name of the ESP), or absent altogether.

I think you mean http://www.tesnexus.com/downloads/file.php?id=8489.

http://www.mentalelfz.com/index.html <-- tutorials and info for it here

http://www.tesnexus.com/downloads/file.php?id=8489. It will copy all non-vanilla files required by an ESP (including ESMs or master ESPs) into a new folder ready for packaging and uploading or archiving.

That's what I was looking for, thanks. I knew there was something out there but I had no idea what it was called