I would think that a CMS is a CMS regardless of the actual content. 

No need for sarcasm. Wektech was just stating something fairly obvious, that a CMS is a CMS is a CMS. Now, if you're looking for specific features in a CMS that would be especially useful for an "Adult" site, you could have phrased your question more clearly. What sort of things would you be looking for in the way of unusual features? Security related features? Some sort of "discreet" interface or mailing address? Various forms of payment systems? Chat rooms? (one-to-one all the way to many-to-many) Galleries and videos? Shopping? Age verification? Ability to accept written submissions and photos, especially with moderation? Etc., etc.

You're probably better off looking around some of the major CMS offerings and their lists of add-ons and themes -- Drupal, Joomla, and Wordpress. Get an idea of what generic features you need and check against their standard list and what's available as extras.

If "price is not a problem", I'll be happy to whip up a nice system for you. $1 million, payable in advance, please.