Check out thingiverse or other 3d model repositories for an already existing make and model of the taxi you want. And I believe there are already services out there that will take photos and design a 3d model of a person, but of course if the photos weren't taken with 3d modeling in mind, it probably won't turn out so well.

But I'm thinking, do you really want a model of him that just doesn't quite look right? As good as modellers are, a figurine is never quite right. Maybe the taxi alone might be enough, so you don't have to look at a crappy figure that doesn't look like him. Especially on the scale I'm envisioning, details get muddied at that size.