next-frame / cycle through all frames?

[David Reitter]

What's a good way to cycle through all frames?

I have defined

(defun switch-to-next-frame ()
  (interactive)
  (select-frame-set-input-focus (next-frame)))

which lets me switch to the next frame. But unfortunately, at least  
in current CVS versions, it seems to be adding the current frame to  
the top of the list so that the next call to  `next-frame' will  
return the previously selected frame. In other words, if you have  
three frames open, it'll only let you cycle between two of them.

Is that actually the intended behavior? (It might be analogous to  
windows.)

If that's so, what's the easiest way to cycle between all frames?

Thanks for your help!