It looks like, if accepted, this would be a feature request,so I'm marking it as such and setting versions to 3.2. You'd have to provide a patch pretty soon to get it in to 3.2, though.
However, I'm guessing that this is something better off implemented via subclassing in your code, since it sounds like a fairly unusual command pattern. (I've only ever seen options after a -- in a unix comand when those options were being passed unparsed to some *other* command that the first command was a wrapper for.)
I've added Steven as nosy, we'll see what he thinks.