On Mac OS X, under System Preferences > Sharing > Edit (Computer Name) there is an option to "Use dynamic global hostname."
Not a lot of information... but apparently this allows you to:
a) Be able to refer to a personal computer by name using Bonjour/ZeroConf even if the computer is not in the same LAN through secure dynamic DNS update (RFC 3007).
b) Be able to see available services provided by other personal computers as if they were in the same LAN through Wide-Area Bonjour registrations.
Apple is now providing such service for free through iCloud via Back To My Mac. But it's limited, for instance, because all the computers need to have Back To My Mac enabled through the same iCloud account. Hardly ideal.
Does anyone know if it's possible, or what it would take to provide such service through Dreamhost using a customer's domain name?