Reader Bryan Lauas sent me a couple of links for 3-wheeled utility cycles. He pointed me to Vincent Budnick's nifty site where I found some pictures of three wheelers in China. Here's what Vince had to say:

A lot of small transportation and service needs are cheaply met by rear wheel drive motorcycle based three wheelers. These are mostly the familiar 150cc motorcycles outfitted with a two-wheel rear axle, and some kind of frame or enclosure.This yellow beauty is a taxi in Chingqing, which is a high altitude northwestern city, so it gets cold. I doubt if it has heat, but I'm sure that the hard shell makes for a much more comfortable ride than the more open configurations below.Both vehicles below were photographed (at night) in Dali. Dali is in a southern region, and is pretty temperate even in January when we were there. I'm not sure of the gearing, but the area there is quite hilly, and these bikes have very small engines.