Awesome! Thanks. I don't know much about the path from idea to standardized feature with the JVM. Is there hope for it in Java 9 or is this much farther out in the future? Probably first and more importantly, what is the chance for this even ever happening?

I'm not sure you'd need to introduce new instructions.

"user-defined value types", i.e. structs, can already be done today by (ab)using the Flyweight pattern and storing data (possibly off-heap with RAII rather than GC semantics) in some byte[].

All a JDK-supplied implementation would really need to do is (1) automate/hide all the painful work necessary to set this up and (2) provide syntactic sugar in the form of operators that can directly manipulate members of these types (+fast implicitly inlined implementations of them, specialized on the member types).