True...there are companies that will offer 100-year, but they are just re-registering it for you for 10 at a time...from wiki:
An end-user registers either directly with a registrar, or indirectly through one or more layers of resellers. As of 2008, the cost generally ranges from a low of about $7.50 per year to about $35 per year. The maximum period of registration of a domain name is generally 10 years.
Some registrars are offering longer periods of up to one hundred years, but such offers involve the registrar renewing the registration for their customer. The one hundred year domain name registration would not be in the official registration database. Some packages of services, such as web hosting, include the domain registration in the total package pricing.