There are several resources for canine carts.
Those of us on Abledogs have
discussed them & many of us prefer
one type over another.
So, here are the links:
DOGGON' WHEELS: http://www.harborside.com/home/d/doggon/
EDDIE'S WHEELS: http://www.eddieswheels.com/
(this man lets you rent to own.)
K-9 CARTS: http://www.k9carts.com/
PET MOBILE: http://www.pnx.com/petmobile/
DOGMOBILE: http://members.aol.com/dogmobile2/index.html
(these are made in the U.K.)
Plus, there are a couple of people
who made their own "wheelchairs" for
their disabled pet. Hope this helps. Kitty