yes, they offer this ONLY if you have "a Reseller, VPS or Dedicated server" service with them. In other words, if you just use them for domain names, then chances are you don't get this.

Name.com offers this service for free to domain registrations: http://www.name.com/faq/create-my-own-name-servers

EDIT: I stand corrected, please see: http://news.ycombinator.com/item?id=3869727

I just tried registering my own nameservers on my NameCheap-hosted domain and it does appear to work even with a plain domain subscription.