A while ago I talked about the need for subdomaining, that people should be willing to sell or rent subdomains of their domains to others, especially if theyhave domains that could be of use to a lot of people, like cars.com. (nissan.cars.com, ford.cars.com, etc.) Really, there should be more TLDs, but until then (or for less common names like kfox.weblogs.com or fox.clan.net) there's IHN. These folks will handle the DNS end of it for you, and let you build traffic to your own site (and make money) by leasing (or whatever) subdomains of your SLD to other people.

They have a few subdomainable domains of their own (like clan.net), and they encourage others to add their own domains for subdomaining. Worth a look see to get an idea of where the net might be going, if nothing else.