This issue came up while working on another thread:
http://bbs.applescript.net/viewtopic.php?id=15169
I believed that a UNIX hard link (see the man page for ln) would have solved the problem, as a hard linked script seems to return the [path to me] based on the link, not on the original script. I really thought I was onto something, until I tried to edit the original script, and it cannot be saved under the original filename if a hard link exists. I tried replacing the file (using the original name), but the link was dysfunctional afterwards.
The Indiana University UNIX tech base:
http://kb.iu.edu/data/aibc.html
States that any modification of the original file will be reflected in the link(s). It certainly works with text and jpg files, as my limited experimentation has shown, but why not an AppleScript?