If you fancy spending some money we have a product that can help with this, it could also save you mucho money on unused software licences

http://centrixsoftware.com

<\shameless plug>

And I am pretty sure you can find that out on SCCM

http://blogs.technet.com/b/breben/archive/2013/08/26/inventory-mapped-drives-in-configmgr-2012.aspx
 

I was able to get this working by deploying a vbs script out via GP.  It's puts everyone's shares in a folder.  So now I just need to make some scripts.  Thanks though!