I’ve been using the Haiku logo for a really long time(12+ years) as you can see by my old post in the screenshot thread (as augiedoggie). That was back in the day when the Deskbar icon was still a bitmap and not vector, but it’s still trivial to change if you know which files to edit. If you build your own version of Haiku then I can tell you how to do it. I have it set a bit too large at the moment, it gets clipped if Deskbar is in one of the mini-modes. This is the modern version…
Edit: The image keeps getting recompressed when I upload it here and makes it look blurry. Looks better on imgur