If you are striving to be a top level competitor in Judo, you would serve yourself well to learn Brazilian Jiu-Jitsu. If you're lucky, you will contact the following guy to help you in your pursuit.
We had the great fortune of having David Camarillo and Mike Malloy conduct a BJJ seminar at our Club in Colorado Springs, Timberline (http://www.timberlinejudo.com). It was the first time I had been exposed to formal teaching in BJJ.
I consider myself to be a decent ne waza competitor, but I can tell you I was blown away by the technical understanding David has for matwork and grappling. It was also neat to see someone who can share his knowledge, teach others his skills, in a fun, relaxed way.
This seminar was exciting in that we had athletes from all over the region, who participate in a variety of different martial arts: BJJ, Judo, MMA, submission wrestling, pancrase, attend the seminar.
Everyone learned something. For Judoplayers, Dave is very good at explaining which BJJ techniques apply to a Judo match, and which don't. It was also beneficial to see someone who has perfected his craft so much that every time he performs a technique, he does it so fast and so powerfully, you get a clear picture of what you should aim for with your own skills.
One of the best ways to be a world class Judoplayer, especially if you're from the US, is to become a skilled mat expert. You'll be able to win more matches, pressure more of your opponents, and beat opponents who are more skilled than you.
If you live in the San Jose area, Dave runs his own Academy. I know if I lived there, I would miss Judo practice to learn the skills he teaches and develop the fitness it takes to fight several BJJ ne waza rounds.
If you don't live in San Jose, and you are interested in learning BJJ techniques that apply directly to sport Judo, contact Dave (firstname.lastname@example.org) and get him to conduct a seminar in your area. You will be thoroughly amazed at the curriculum he teaches and you will be giving your own competitors an unfair advantage!
Here's a link to his website: http://www.akakickbox.com/dave-bio.html