If you have your ESXi or KVM VM environment in place, it takes about an hour to install vSCG firmware, configure interfaces, apply licenses, join a few APs, and configure a set of WLANs.
Then its just a matter of getting familiar with domains/AP-zones associated with
your different tentant(s), and setting up their individual WLAN requirements.
You are probably correct that not a lot of IT hosting companies have deployed the
vSCG yet though, but we anticipate a busy 2015.