What you are specifically looking for does not exist. There are
technologies close like Windows Clustering using Virtual Network Names
etc or DNS round robin. The real issue appears to be that your clients
are mapping network drive independently without any standardization.
You should implement a standard login script for your users so that
when this type of event occurs you can change the server name in the
script and not on all the machines.

As far as the data. Using a resource kit utility like robocopy would
likely do the trick. Make sure you execute the script on the server and
not from a Windows client for performance and speed on the copying of
data.

Dave