Running docker-machine without admin privileges on VirtualBox

I’m trying to run DM without admin privileges. As far as I can see the the only privileged operations to required to create a VM are creation of the host only adapter, configuring of it and addition of the DHCP server.

It should be possible to reuse an existing host only adapter and thus run DM as a normal user. I’ve tried specifying the CIDR of an existing adapter and no joy. I’ve noticed that DM will create a second VM using the same CIDR using the host only adapter that it created for an earlier VM with admin privs so it can obviously can reuse an existing adapter. Any suggestions?

Why do I need this? Working in a corporate env with no access to admin. I can setup host only adapters during the VirtualBox install but need to be able to get DM to use them. I could build my own boot2docker scripts etc but would prefer to use DM; or if needed extend it.