you rock climb and then hook a hammock to the cliff and sleep in it?

Big wall climbing?

Are you thinking of a port-a-ledge instead of a hammock?

http://metoliusclimbing.com/bombshelter.htm

What you are looking for is a portaledge. Check out the link!

Portaledges are used for big wall trips (where you spent atleast one night on the wall).

You will need advanced skils in anchoring to use a portaledge.

Have fun!

The type of climbing u r talking about is Grade V or higher (YDS system, multi-day climb) & is usually Class 6 which is ''aid'' climbing - using ropes, pitons, & assenders to climb a wall which does not have big enough holds to climb using ur hands & feet.

The ''hammock'' is called a Port-a-ledge & is a very light weight platform that u assemble & hang from an anchor. You haul this up the mountain with u & sleep on it each night u r on the multi-day route. An interesting fact is that climbers also sleep with their harness on & tied into an anchor so they do not fall off!!

Good Luck