I would be in support of an open-source Vagrant box that simulates DreamPress. DreamPress has a relatively complicated stack, and especially given the exposure of HHVM, which may fail in corner cases (as well as other issues, like memcached w/ advanced custom posts, Varnish w/ cookies), customers may be more willing to make the switch if they can test a high-fidelity simulation of that environment.
WPEngine already does this with Mercury Vagrant (HgV). My decision to use DreamPress was actually based on the availability of HgV, but that environment has some key difference (Nginx instead of Apache, no SSL support via Nginx termination).
Let me know if I can help get this going.