It should be noted that the new x-36 cassettes were designed for the drive trains of modern 29'r mountain bicycles and that the cassette is supposed to go with a stronger hub body to withstand the extra torque although a standard hub should stand up to this well in all but the most severe use.

Although Shimano says they offer individual cogs, these are sometimes very difficult to find but as noted, other companies do offer single cogs.

Back in the old days Suntour offered an Alpine group that had a 14-36 freewheel and this had an AG derailleur which was designed to handle this massive rear cog.