If you hold this piece of data somewhere in inventory, it's something you could pull via the MBSDK and a dynamic query for instance - an example of which is shown in the article detailing the MBSDK here -- Getting Started with the MBSDK (Example Scripts Included) .
So as long as you have either the username (/owner) string (and/or potentially - the full e-mail address as custom data) ... that'd solve that problem, no?
And you can use this for new kit as well, by just populating that data for new devices too (assuming you have an "intended owner" in place). Otherwise, a simple script to either populate that field and/or create a mini scanfile to create that data field in the inventory (inventory files are "just" text files, so it's not hard) when an owner has been assigned.
That way, you'd have a consistent proces flow for instance.