I was in New York this past weekend and saw a yellow cab TCH. That should be a good test of mileage in the city and long term reliability. It would be interesting to see what they get for mileage in that environment.

There are many fleets that are test driving hybrids. Because they do a lot of start/stops in metropolitan areas, I can't see them having a huge savings, it's not like they can cruise for several miles in EV mode.

it's not like they can cruise for several miles in EV mode.

I have noticed that my car will sit quite a while in E mode with the AC on before the ICE kicks on. I would imagine the TCH will get lousy milage in NYC but I'm guessing with all the sitting done in a taxi, it will still have a significant milage advantage (even with luggage on a trunk rack) over the normal cab.
I know most taxi companies keep great preventative maintenance logs and hopefully they will share this info.

The sitting isn't the problem, it's the constant need to accelerate for very short distances that seems to kill the gas milage for me in the city, or in suburban rush hour. Interestingly, if rush hour is going really slow, I get very good gas mileage, but its the 10-20 miles per hour rush hour that kills me.