>>> It's not perhaps the solution that would suit everyone, but I'd bet 
>>> some users will prefer that to the way they are currently displayed. A 
>>> third option would indeed be a kind of pop-up buffer.  And there are 
>>> probably other options.
>> 
>> Popup buffer and popup frame (perhaps a child frame?) are IMO the only 
>> viable alternatives that are worth having in Emacs.
>
> A popup frame is not an option for terminal users.  A popup buffer could 
> be an option, but if I had to choose between the two, I think I would 
> choose the mode-line one, which is IMO less disturbing.
>

And here is (a first draft of) the code for a popup buffer.