Best Way to Grant Read All Permission in SQL Server 2008 R2?

For future databases, do this because all DBs are created from model

USE model
EXEC sp_addrolemember N'db_datareader', N'MY_DOMAIN\SQL-READ-ALL'

For existing databases, just run what you have above, once

About the restore: you can set up an Event Notification for the AUDIT_BACKUP_RESTORE event. Not for the faint of hearth, since programming asynchronous event notifications is not exactly easy, but it can do the job you're asking. See Implementing Event Notifications.