Spent the holidays in the Seattle area. I am always delighted to see and make use of bright yellow Prius taxis. We landed in Seattle and took a Prius taxi from Sea-Tac to the ferry and back. The taxi drivers speak well of their Prius taxis.
Up the road in Vancouver there are a lot of Prius taxis. Second gen, 3rd gen, and the numbers of Prius v taxis are increasing quickly. It's funny to driving downtown and notice you're surrounded by Prius. Or have someone try to hail you, LOL.
The Prius v makes perfect sense as a taxi because of the flexible rear seating arrangement and large cargo area (especially dealing with international travellers). They may not get under 5L/100km but at least the passengers will be comfortable and there's no need to tie the tailgate down with string. That being said, I have noticed that Camry Hybrids are getting some attention as taxis even with the smaller trunk. It's mostly in cities where the airport is a good distance from town so I guess the drivers want passing power.