I need a really simple plain red sweater/leash hybrid for walking Petrovich around when he grows up. He already really enjoys his trips to the park but hes going to outgrow his kitten cruiser soon (he is actually still with the breeder, shes requesting I look into getting one for his adult life since he /really/ enjoys it more then any of her other cats)

I have an adult sized indoor sweater for him so i can provide measures, but I need one of those cat harness/leash hybrids it needs to be fairly... warm/sturdy. He is a male devon rex so he does get chills sometimes. Throw me a line if you know someone who can make these for a low cost. Im a poor student so I don't have a massive budget haha, most of the ones I've found around the internet have been 80+ without shipping, and I cannot afford that!

Any idea how big it would have to be?