Hi Monsoon,
I see you haven't received a reply to this question, so I figured I'd take a stab at it.
I don't own the DVD you reference, but I have done some chin na training with a concrete paving stone. I find the mechanics of the grip are different from the grip used when throwing a kettlebell, since the fingers naturally curl around the bell (so less "gripping" is needed) but lie flat against the paving stone (so much more gripping is needed). Also, when I throw the paving stone I typically throw it straight up and catch it straight down. While I squat while tracking & catching the stone, the exercise works my grip/ forearms & shoulders more than a kettlebell (which works the lower back & hamstrings more).
The paving stone I have is really rough concrete, so I use gardening gloves when doing exercises with it. I had some pretty bad abrasions when I started, hence the gloves.
As an aside, about a month ago I purchased some "Fat Gripz" to use when I lift weights. When used with pulling motions (pull ups, seated rows, upright rows) my forearms/ grip get a fantastic work out too. Bodybuilding dot com had a sale not too long ago, at which time I picked these up for about $30. I would NOT recommend paying more than that for these - what you're getting is an industrial grade rubber grip that you can snap around an existing bar. It's very convenient if you are going to use these on different bars, and the quality of the rubber appears to be very good, but I find it irritating that the price is so marked up.
Ross Enamait, a very inspiring strength/ conditioning coach based on the East Coast, has a FANTASTIC blog with a whole section dedicated to homemade equipment. If you go to this section of his blog:
http://www.rosstraining.com/forum/viewt ... 7#section3 , and scroll down he has a section devoted to grip training. Master Ross was a lifesaver when my kids were younger and I had to rely on 20 minute no- or low-equipment home workouts to stay in shape.
Hope you find this helpful.
Best,
Greg