FINN BV in the Netherlands, a producer of clapskates for iceskaters, has a line of clapski bindings. The system apparently is in use on the World Cup sprint circuit.
With a conventional ski/binding/boot system, the the pivot point between the boot and ski is in front of the ski boot. Ski boots for skating also tend to be high cut:
The clapski system moves to pivot point to under the ball of the foot. A stiffer, lower cut boot is also used:
The bindings are constructed of aluminum and come with various springs, rubber damping sets, and plates for mounting the binding on the ski.
The company makes four models:
The Regular is made of strong aluminum and a 7000 aluminum hinge. The Regular comes in five colors (Orange, Red, Silver, Black, and Blue) and is the entry level model:
The Semi Pro is a stronger system also made of strong aluminum and a 7000 aluminum hinge. the XC Ski Racer comes in models: Gold XC, Skavi, and Blue Flexible. Each looks slightly different, and it's unclear when you would use one binding over the other:
Semi-Pro Gold XC
The Professional is made entirely from 7000 aluminum, and it appears you can realign the binding. There's also a built-in grease system:
Finally, there's the Olympic version, with a changeable damping unit, 3 different spring options (4 standard springs, 4 marathon springs, 2 mid-springs), and adaptation plates to mount on your ski:
With each of these systems, you need a speedskating boot.
It is somewhat difficult to change skis with this system right now - it has no quick release! You have to unscrew a screw to change skis.
Once I locate a copy of Thomas Stöggl's paper titled "Double-Push Skating and Clap-Skate in Cross country skiing, technical developments for the future?" (presented at the XXIV International Symposium on Biomechanics in Sports, July 14-18, 2006 in Salzburg, Austria), maybe i can give you a better idea of what the pros and cons are of using the clap system...