Multiple return type from object factory possible?

[deed]

class A                  { ... }
class NonContainer : A   { ... }
class Container : A      { A[] container; }
class NC1 : NonContainer {}
...
class C1 : Container {}
...

A getO(string info)
{
     switch (info)
     {
         default     : return new NonContainer();
         case "info1": return new C1();
         case "info2": return new NC1();
         case "info3": return new Container();
         case "info4": return new NonContainer();
         ...
     }
}

void foo()
{
     auto o = getO("some information");
     if (is(typeof(o) == Container) { ... }  // Doesn't work.
                                             // Type is always A.
     ...
}

Is there a way to make getO return the most specialized type of 
the instantiated object in the switch statement to enable this 
pattern?