Well, I'm in the same situation now and yes, I want to achieve this on the Campaign level.
Why? Because I use the Campaigns as intended. We send some batch invitations, but our Sales team can also add people to the campaign. They add them as a Member, we listen to that so there's a trigger that sends out the invitation mail and puts the status on invited. Then they can fill out a form to register, so the status becomes Registered... And so on... All of this is reflected in SF and finally our sales can follow up on their people in the campaigns.
BUT: yes, we want to be able to use a "Relationship Owner" (or in our case: "Campaign SPOC") per campaign. Now we use the Lead/Contact Owner for this, but the Owner is not necessarily the one that invites the people for the event (e.g. a private after show drink).
And yes, I can access the fields in the Smart list filter constraints, but I can't access them in a mail (to set the from-name and mail, to sign the mail, ...)
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