Sounds to me like they missed an opportunity to also host, in addition to being a prototyping site.<p>The correct answer for that client was "If you want to host that site with us, the URL will be X and it will cost you Y per month."<p>Chances are they just wanted free hosting, but if they didn't, you've got more income and an additional revenue model. Without much work.
Even if they don't want to host it themselves, they could partner with a host and coordinate the single button click push to production for their customers.