Is there an alternative private messsage module that integrates with Views?
You can also consider theming Private Message.  Private Message is an extremely powerful module that offers a much higher degree of customization than some sites may need (messages can be sent to users + roles at the same time, etc.)

For my site, I added several tweaks to actually limit/reduce Private Message's functionality (users can only have one thread per user, users can only message one user at a time, users cannot send more than three messages in a row to the same user, etc.)

Messaging systems are pretty complex so I found it easier to start with the huge number of options Private Message provides and then reduce them.

You could also help work on privatemsg views integration, though this is a huge project.