I run a number of virtual machines as part of infrastructure testing and I've separated them from my local LAN by placing them in virtual networks configured within Fusion.
As the networking configuration is somewhat limited, I tend to run a pfsense firewall VM to connect all the LANs together and provide firewalling etc... as such, this VM is running pretty much anytime I power on my Mac. As a result, I'd like to be able to run it without a separate window.
I'm aware I can use the vmrun binary to do this, but a simple toggle in the Settings / General pane would be much simpler.