Personally, I have an actual production need for this. After I read the paper, I idly thought of implementing Class::Trait myself, (but am waaay too lazy).

I've got a Base class, called Object::Base. I've also got Object::Singleton and Object::ReadOnly. So, now, I want to be able to create a readonly singleton. Ok. Not a problem. Except, I don't want to create a Object::ReadOnlySingleton class. (I anticipate adding 3-4 other orthogonal attributes.)

The problem is depth-first method searching. There's some dovetailing between how O::Singleton and O::ReadOnly do their work. O::Singleton calls a method that O::ReadOnly overrides, and vice-versa. If I inherit from them both, I miss whichever is second in @ISA.

So, in short - yes, I want this. I'll be treating Traits as a neat implementation of Decorator, but it still works. :-)