I have the best pet 4 wheel stroller.
http://bit.ly/MB1olt
I wrapped a leash around the stroller bars through the gap where the back zips on. The problem with that is Lola kept getting it wrapped around her neck.
My other idea is to unvelcor the bottom cover, pull the parcel board out, wrap the leash around it and have it come up from the back velcored area.