A-Conman was design specifically for adult webmasters. Do a search here and you'll find it. It's open source so someone will have fun playing.
I've been toying with Postnuke for the backend for a large AVS site I'm putting together. It's got all the gallery and banner admin features as well as some modules to keep surfers occipied and clicking. Check out PortalZine for the best addons and modules.
http://www.portalzine.de