There's four spaces between *scratch* and All because they have
different faces...  which makes me wonder why there's trailing spaces in
the buffer name at all, instead of just three spaces after the buffer
name in the mode line format?  But that's a different issue; the patch
looks great.

There's also the question of allowing a value of `long' to
mode-line-compact -- which would only compact the mode line if it's
longer than the window width.  Would that be difficult to add?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no