I did wonder if being fully free might encourage more users who might fund you in other ways but Borg backup isn't making very much like that, so perhaps not:
https://www.bountysource.com/teams/borgbackupThe AGPL license might be a step in the right direction (for your requirements). It aims to at least ensure that if companies use the code to provide a service to other users, they have to release their changes. You can sell those companies a different license if they don't want to accept the AGPL (you'd have to have a contributor agreement to assign copyright to you though, to allow you to relicense code at your discretion like that).
Or there is the open core model (like nginx-plus), where you provide the code under an open source license but provide some additional "enterprise" features (like your vmware stuff) to only those that pay. I'm not a fan but it seems to work for some.
Anyway, duplicacy sounds a great design. All the best with it!
