Gibson has just reissued Tobias basses, and it looks like lefties will be available! The only one I see in stock at the moment is the Classic V at Motor City Guitar, but man, what a beautiful bass:
https://motorcityguitar.com/products/to ... 5715651650
If you watch this demo of the full Tobias model line, they briefly show both lefty Killer Bs and Growlers too (:49 mark and 2:40 mark):
https://www.youtube.com/watch?v=xZplmi_-6IY