Hi out there,
Jerome, a guy from DivX, has called my attention to No Screwdriver Needed, a Robotic LEGO Channel that contains high-resolution DivX videos on LEGO Sumo battles. He told me that they have an Annual LEGO Sumo Championship in their company (for three years now) and have been recording and broadcasting the event this time.
There's a great video on many NXT bots (and a terrific RCX one) fighting against each other.
Do not miss that!