I have a rule that runs any screenshots I take through optipng; I'd like to be able to set the title of a displayed notification to "Optimizing “<file>”" (instead of "Hazel Alert") and set the body/info text to the last (non-empty) line of the command-line output (stating whether it's already optimized, or info about size savings). I can do this if I use the "display notification" AppleScript command, but then the notification's icon isn't Hazel's.
(This is really just a perfectionistic request, and I won't be crushed if it never gets implemented!)