UPDATE 2/23/2016 I think my original question was confusing, so I am going to rephrase it: I have my own dedicated nameservers running cPanel DNS Only! I want to know how to give other people vanity nameservers!
Our company has its own dedicated nameservers running cPanel/WHM DNS Only, which are using the hostname ns1.ourcompany.com ns2.ourcompany.com and so forth.
One of our clients is a reseller and wants to use our nameservers but would like to white label them so that it says ns1.theircompany.com, ns2.theircompany.com and so forth.
Is there a hostname alias option that the nameserver will respond to? How would we achieve this?
I've read many time that using CNAME for nameservers is a really bad idea, so I am guessing that is not an option.
UPDATE Feb 2016
I've created A records to point to the nameserver IP addresses and it works! I don't know why it works and how I could prevent someone from pointing to them with a different domain. So if I pointed them to CloudFlare I could use cloudflare as the nameservers? How would CloudFlare prevent that? Also why would creating a CNAME record instead of an A record not work? It has been working for me on Amazon Route 53.