Not as hardcore as some of the amazing machines in this thread, but here's my latest dog chariot: a 2010 Globe Live 2, which I bought for my father and his dog, but he never used it and regifted it back to me a few years later. The Jtek bar-end shifter is the best-shifting bike I've ever ridden. And Nena digs riding on it just as much as my old shih-tzu Angel (RIP).
Next step is a 7800 crankset and outboard BB, so i'm not pedaling like a bowlegged cowpoke.









Alfine 11 hub with Jtek bar-end shifter, Shimano XTR brakes with Tektro levers, and a 52cm wide bar to fit around the dog's compartment.