When I get the Event ID 1077 warning in  the Event Viewer, I'd like it to show me the actual mailbox name not a number.  Where would I do this?

Event ID 1077, Source: MSExchangeIS

The mailbox 7b0a66a2-146e-4dc5-a3b8-7010e48a03d6 on database f67cb406-1fbc-4330-a1e6-190d11256b7f is approaching its storage limit. A notification has been sent to the user. This warning will not be sent again for at least twenty four hours.

Win2012/Ex20

You can take the GUID following mailbox and use it as the identity in Get-Mailbox.  Unfortunately I dont think its possible to provide that in the event viewer.

What is the command I would use in ExchangeShell to cross reference it?

Get-Mailbox and use the GUID as the identity.  So in your example you would use 

Get-Mailbox 7b0a66a2-146e-4dc5-a3b8-7010e48a03d6

That is fantastic! 

Thanks. :)