We use a product called Wise Install Master to generate our installations. It does not let you run .vbs files, but it does let you run .exe files. So we can place the code in the .vbs sample in an VB application.
Other installation products could also use this functionality such as InstallShield.
Using a .vbs or .exe file we can automatically generate a Virtual Directory/multiple Virtual Directories. The sample code is the contents of a .vbs file used in the installation of SSW Access Reporter for IIS to create a Virtual Directory called 'SSWAccessReporter'.
Sample .vbs file that Creates a Virtual Directory - Click Here
PLEASE NOTE: we have renamed the .vbs file as .txt in order to view it in the browser. To get it working it needs to be renamed back to .vbs
For some more really cool links see your C:\Inetpub\AdminScripts directory.