Not strictly a commute, but massively enjoyable all the same and a fantastic way of exercising the dog. I dusted off a fat tyred bike and flashed around my local country park. In the summer I am going to ride around on my crosser, TT the dusty tracks with dog in tow. For me cycling is so much more fun than walking and I only run when being chased, so this seems a great option for my crazy dog.
Next I have to attempt this with my son in the cycle trailer at the same time, should be interesting!