No, haven't had to do that. I did make a sweater for my chi x (about small cat size) out of a sleeve of an old woollen sweater. The sleeve cuff becomes the neck, you then cut holes for the front legs to go through and then trim the sleeve arm to fit the body (and hem for neatness). It worked but he hated wearing it and our other dog kept pulling at it. I ended up making him a fleecy/woolen bed cover as it only really gets cold here at night in the winter.
If you don't mind me asking, why does kitty need a sweater? Our cats despise collars, I don't think I'd have a hope of getting either of them clothed.