Board Thread:Support Requests - Getting Technical/@comment-11413557-20140222003322/@comment-366087-20140223133604

According to Help:Custom namespaces, a wiki can only request 3 Customs, plus their associated Talks, although the Talks can be skipped upon request.

The tricky part is to NOT have a page starting with the New Custom prefix before it is enabled, as that would evaporate the contents of those pages. You'd have to rename such pages, then name them back when the Namespace is enabled.