(overlays-in (point-min) (point-max)) returns what you would expect:
#<overlay from 397 to 400 in *scratch*>

This was with a slightly altered example, I removed the overly long comment
as it took forever to draw.  100% cpu resources are used when the line is
being drawn, and it seems to be redrawn many times before it's finally
done.  Then all is well until something causes the line to be redrawn.

I'm not sure what 'RSS' means in this context, but I assumed you wanted a
screenshot of top:
http://imgur.com/Rv7Z5Ly

Unfortunately emacs isn't shown here, but X always takes the blame for the
resource use, never emacs.  I have tried interrupting whatever is going on
with C-g after toggling debug-on-error, but I'm unable to interrupt
anything in this manner.

FWIW I cannot reproduce this bug on any other computers either.  My desktop
computer runs an almost identical software stack but is unaffected.

I will try to attach a debugger, but my computer is quite unusable after
triggering this problem, so it may be difficult.