The new Shimano cassette is being specked on 29r's and could see some serious touring cyclists and tandem riders liking these extra teeth on the cassette and the beefed up hub that goes with it and am sure other premium hubs like Phil Woods could handle the extra stress.

With some off road set ups this cassette would allow you to run a double or in come cases a single chain ring and believe the new 10 speed XT group has a 36 to allow riders to stay in their middle ring longer.

This is nothing new as some 40 years ago Suntour offered touring freewheels with as many as 36 teeth and only they and Huret made a derailleur that had the capacity to handle this kind of spread / range although the top gear was usually a 14.

These were run with half step gearing as the jumps between the rear cogs was huge and it needed that to provide smoother shifting and were popular with early mtb pioneers as they offered the most range possible.

High tooth count Suntour freewheels are fairly rare... the 36 tooth model is the stuff of legends as few people have ever seen one.

I have one that was given to me along with a Huret Duopar Eco touring deraileur which was the only non Suntour derailleur that could handle this kind of range in that day.

Modern long cage mtb derailleurs make this easy and many folks don;t realize that once upon a time your basic cluster stopped at 28 because there were few derailleurs that could handle more than this and changes were made up at the front.