> I've used rotated images to display a spinning 'busy' indicator in the modeline
> in the past.  The corresponding package currently ships with a set of
> pre-rotated images, but generating them in Emacs would be more convenient.


I used runtime svg generation for similar task, to display video notes (and
its progression) inside Emacs.

It worked pretty nice, see the demo -
http://lgarc.narod.ru/pics/IMG_3498.MOV

-- 
lg