nmaping 2^96 possible hosts doesn't seem like a good idea
Of course, it's stupid...
What are you exactly suggesting?
Exactly? Nothing... I can't.
I dont know anything about your machines, your subnet structure, your intentions... discover all hosts (maybe computers, routers, mobiles, consoles ...) in a ipv6 subnet is a complex work. You have to ponder numerous factors and curry out a good thinked strategic plan. A ping scan maybe sufficient in determined situations, but the most of times, isn't it.
I tell you about nmap thinking in all this. You will not find a simple option in nmap manual to do this, you will find a lot of things that you can use in your plan.
Yes, it sound like a very very freaky hacker sentence...
Take a look to http://www.faqs.org/rfcs/rfc5157.html
and read all the links -if you have time-, all are very interesting. And forgive my previous post, it was very presumptuous.