nope they come in boys - as someone who had a 10th percentile weight and 90th percentile child (x2) can attest.
I loved baby legs, bonds tights that looked like jeans, bonds pants one size too big for length (but we use cloth so that fills out the bum). When all else fails and you are desperate, cut the feet off the onsies and sew on socks (cos they're stretchier than the feet and can be made longer). I made pants for my little guy as well.
Best and less make clothes that are huge and while I often had to either pin or adjust the waist at least the length was good. oh and they make polar fleece sleep suits that are loooong!