Letting out my inner conspiracy theorist for a moment, a prism can be used to split light. For example, think of a pentaprism mirror in many DSLR cameras.
Did the NSA choose "PRISM" because they are splitting the signal upstream of providers, thus giving private companies plausible deniability?
Yes, but JSON is JavaScript Object Notation, not (PHP|Ruby|C#|Java|Other) Object Notation. Therefore, since JSON is a serialization of JavaScript, it recommends that you should adopt the JavaScript convention of camelCase.
Usergrid ( https://apigee.com/usergrid ) addresses at least some of what you're looking for. If you try it, let me know, as I'm part of that team that's working on it.