Amnesty is one time use and they already used it.
No way Knicks can sign Paul next year unless some bonehead franchise trades them over $20 million worth of expiring contracts for Amare (someone's probably stupid enough to do this.) Even then, they'll have approx $55 million on the books for next year so they'd still need to make some additional moves to clear up enough space.
Only legit possibilities (i.e. teams with cap space and actual good players) is Dallas, Utah, New Orleans, Atlanta, and the Clippers.
Count out Utah because when was the last time a superstar signed there?
New Orleans has huge upside but is way too young.
Atlanta is a dark horse. CP3 + Smith + Horford would be a nice trio. Plus it's close to home for Paul.
Choosing Dallas over LAC would essentially mean he'd rather have 2-3 years of whatever Dirk has left over the next 5-10 years of Blake.
I still like the Clippers. Not only because they have a talented team, but also because they can offer him an additional $20 million.
EDIT: You can add Indiana to this list if they can trade Granger for an expiring. But who really signs with Indiana?