Combine all forms of textual messaging

I have always thought the distinctions between email, IM and texts were artificial. I would like to see them all integrated under one wrapper, with distinctions that preserve the conventions of the current usage. 

• Text is an "immediate priority" email (more than ordinary "high priority" like in Outlook). Optionally, your client or email service can let you require a PIN or white-list relationship to accept incoming as immediate priority.
• IM is exchanged in real-time, and optionally saved as email.