I'm hosted on Unix and have the following folders:
/home/me/dev (development site)
/home/me/live (final live site)

vhosts is pointing to the mydomain.com directory and I have a symbolic link pointing to the required folder:
ln -s /home/me/dev mydomain.com

This allows me to run tests in /dev without messing with the live site files. When happy I push my changes over to /live. If I want to check /live I just change the symbolic link to /live.

Of course I can only point a symbolic link to one directory at a time.

After launch, I will need to be pointing to /home/me/live/ but would still like to develop in the /dev folder when necessary.

Is it possible to configure Apache or Unix so, when visiting mydomain.com, it will read my ip address and serve me /home/me/dev/ whilst the rest of the world are served /home/me/live ?