Velociraptor author here. We don't yet integrate with Docker, though would like to once there's some kind of standalone mode (see https://github.com/dotcloud/docker/issues/503 and https://bitbucket.org/yougov/velociraptor/issue/14/investiga...).

Velociraptor does use LXC containers though, and provide the same kind of buildpack support as Dokku, plus a nice dashboard with streaming updates on your processes and some help for managing all the config for your instances (if 2 apps use the same database, you only have to record its URL in one place).

We're running dozens of apps and hundreds of instances on Velociraptor at YouGov, but it still has plenty of rough edges.