Value type, ref type, how about something in between?

[The Anh Tran]

   According to D spec,
     structs, unions are value types.
     classes are ref types.

   But this world is not perfectly described by the above 2. There are 4 
cases:

   1. Value storage class inside value type.
       class C {};
       struct S {};

       struct Outer
       {
          C cc; // ref storage for ref type. This is the rescue for 
splitting copy problem. D language's creators wanted this behavior. If
          S ss; // value storage for value type. OK.

          void funcC(C c) {} // ref param. Correction for splitting copy.
          void funcS(S s) {} // value param. OK.
       }

   2. Value storage class inside ref type.
       class Outer
       {
          C cc; // ref storage. Correction for splitting copy.
          S ss; // value storage. OK.

          void funcC(C c) {} // ref param. Correction for splitting copy.
          void funcS(S s) {} // value param. OK.
       }

   3. Ref storage class inside a ref type.
       class Outer
       {
          C cc; // ref storage for ref type. OK.
          S ss; // How? Wanted ref, but value storage here

          void funcC(C c) {} // ref param. OK.
          void funcS(ref S s) {} // ref param for value type. OK.
       }

   4. Ref storage class inside value type.
       struct Outer
       {
          C c; // ref storage for ref type. OK.
          S s; // How? Wanted ref, but value storage here

          void funcC(C c) {} // ref param. OK.
          void funcS(ref S s) {} // ref param for value type. OK.
       }

   I can solve case 3+4 by wrapping struct S inside a class template. 
But can we have a nicer / straightforward syntax?
   Is there any problem that prevent ref storage class declaration for 
struct types, sir?