What kind of dog should i get?

i live in a townhouse, i have a rabbit and a snake and i want a dog who stays real small and won't really go after my bunny. small enough for me to hold and put in my bike basket. i also want a kind who bods well because i plan to train him to walk off the leash and follow me. plase include sze and weight of the dog in your awnser.thanx.