Getting our clients to add a domain is nearly impossible. Currently, our team will go in and set up a wildcard domain like client.ourcompany.com. It would be nice if we could automate this but nothing (from what I see) domain-related is currently supported in the API docs.
Of course they can always go in and add their own DNS records and change it, but it would be very nice to get them a functional account with live funnels automatically.