64-bit array functionality implemented via libraries?

[Joe Darcy]

Hello.

As another point in the design space, assuming indexing access syntax is 
available for user-defined types and the existence of collection 
literals, I'd like to see what implementing 64-bit array functionality 
via libraries would look like.

A libraries-based approach that does not require VM changes, but could 
benefit from them later, has a higher probability of being included in 
JDK 7.

-Joe