not yet. If anyone else could kindly describe step by step, i.e what to add in the header.php so that the form appears which check the subdomain name availabilty across multinetwork.
Ideal would be that the admin add all the networked domains at the backend. At the fron end the users pull down the networked domains in a form and search for name. Up on clicking search, the result is displayed whether the name is available or not. If available, the user just go ahead to register it.