Looking for software to document orphan files within a large website.

I'm working on a project that requires me to completely build out a new website based on content from the current site. I need to find all of the orphan files within the current site to see if they can be deleted without worry, or if they were orphaned through mistake.

The problem I'm running into is that the size of the site (approx 65,000 files) is locking or confusing most software apps I've found. I tried Dreamweaver 8's reporting tool which after an hour of checking links could show the orphan files, but when I output the results to a txt file, it only showed the broken links, not the orphan files.

Any thoughts?

Xenu