If you create a shortcut to the script using a script you can specify the icon file if it is either an EXE or a DLL file.
There are many free utilities that will convert an ICO file to a DLL for you. I like gconvs40.exe. Search Google and you should find it.
This would only change the icon for that one shortcut and not all VBS files, but it sounds like it would accomplish your goal for this script to be put out on many machines.
I hope you find this post helpful.
Regards,
Mark