Any interest in a multi-stage short url script

Working on a whitehat project I developed a little php to protect downloads by using 1 time use links. Part of the problem we faced was passing the link through facebook, is that facebook visits your link first ~ so we learned to detect and deal with this case. I suspect this is the same method they use to check/block bit.ly/tiny.url redirects to blocked domains. Any interest in fooling facebook to thinking a link goes one place, but then the link takes the user somewhere else? A blackhat tinyurl clone in effect...