The Sakuraba instructional is pretty good. He shows some simple high percentage moves. The best material on it IMO is his section on arm bars from side mount.
Although he didn't show my personal favorite arm bar of his. It was an AWESOME set up by him. I forget who he did it to. But he was sitting in side mount, with his arms draped over his opponent, relaxed. The bottom guy didn't know what to expect. All of a sudden, Saku EXPLODED with punches to the guy's face, out of nowhere, just rapid fire; BAM BAM BAM! Instinctively, the bottom man put his hands up to his face. Biiiig mistake. Saku grabbed the near arm and armbarred it. I want to try this, but it's a move that seems like it'd be more effective in a match than in the gym, because it relies on that rapid fire, hard punching; something you wouldn't want to do if you like your training partner.
Hatmaker has some good stuff. Whenever you buy his material, you can be rest assured a lot (if not all) of it is going to be old school western empiricism. His stand up is based on old school bareknuckle boxing, and his submission game is based on catch wrestling.
I've taken a look at Shamrock's book. He's actually got some pretty cool stuff in that book. The coolest move I saw was what he calls a "Figure 4 Takedown." Basically, you establish a deep overhook on his (in this case) right arm while standing. You take your right hand (the one that's not overhooking), and put your palm against his sternum. Then, you grab your right wrist with your overhooking hand, so in effect, you've Figure-4'ed over his right arm while posting on his chest. Step in deep, and do the same movement you'd do for a "*** Whizzer;" kind of an arch and turn movement. Puts him over your head, on his back. I love takedowns like that.
If you don't mind not understanding what people are saying (unless you speak an advanced level of Japanese), I really recommend the 100 Submission Arts DVD by Hidetaka Aso.
Hidetaka Aso is the founder of SAW (Submission Arts Wrestling), also known as Combat Wrestling. If you've seen the Takanori Gomi grappling video that's circulating around the SD forums, this is the event he's competing in. Aso shows some really cool moves, and shows lots of high pain maneuvers. It really looks like and has the feel of one of those old-school catch wrestling sessions, where you can make the bottom guy just scream.
http://www.budovideos.com/shop/customer/product.php?productid=16705
Here's the link to the video.
Also, you can't go wrong with Erik Paulson from what I've heard. The guy's a total expert at shoot wrestling, and Stephan Kesting, who I have complete trust in, recommends him.
I don't know if you'd consider it catch wrestling, but if you're including just any Japanese submission fighting, you could always go with Bas Rutten's material. He learned most of his submissions out of Pancrase dojos, so if you're considering Shamrock catch wrestling, Rutten falls in the same category.
Bas' Big DVDs of Combat are probably the best investment you can make if you're looking for instructionals. Over 12 hours of material, and no repeated moves. He's not lying when he calls them Big. I've had these DVDs for 8 months and I still don't have every move memorized from them.
https://www.basrutten.tv/index.php?page=shop.product_details&flypage=shop.flypage&product_id=25&category_id=2&option=com_phpshop&Itemid=65
^^ Link 1, from his website
http://www.budovideos.com/shop/customer/product.php?productid=20132&cat=311&page=1
^^Link 2, from budovideos.com. Bas is a great guy, so it's not his fault, but the people he's hired to manage his merchandise aren't always the best at it. They're all good people I'm sure, but I was one of the people to pre-order these DVDs the first week of January, and have to continually deal with delays until I finally got them in the middle of April. So I would buy them from BudoVideos.com. Bas still gets the money.
The DVDs are 115 bucks, but worth every penny. If anything, they're worth way more. "Example: The leg lock DVD itself, has over 60 leg locks on it plus right away after every leg lock, he shows you how to stay out of it and if you are caught with it, how to get out. Same counts for all the other DVD's." (taken from Bas' website)
