[CaraT]

I thought strollers for dogs were crazy...then I realized that with 3 or 4 Yorkies that we could not put enough baskets on our bikes to take them all with us. So we got our dogs a Burley Tail Wagon last year. It is a Stroller and a Dog Wagon that you can pull with your bicycle. It lets me take our dog in many places that they would not be welcome on a leash...like a our local library. It holds up to 75 lbs (so stuff and dogs). I put a medium crate liner in it and we love it.
It was about $500 and we got from our local bike shop where they assembled it for free. You can also get them directly from Burley and it is easier to assemble than a kids bike. I talked to some folks in our neighborhood (urban) that had Burley Wagons for their kids and they really liked them. Also, not having kids I did not know much about strollers, so I asked around and get the option with the one big wheel in the front. Folks who push kids in strollers said this is much better for going up and over curbs where the sidewalks don't have the nice soft ramps where you cross the street and for rough terrain like gravel paths. It lets us walk with the dogs to places that are too far away for them to walk there and back. Also, an added benefit is that people in cars can't tell if it is a stroller for kids or dogs so they stop and let you cross the street. We have it for a year and have had no problems with it. Very happy we got it.
For a less expensive alternative. I have a friend who just got a double stroller at Costco and took the kids seats out of it.