Hi Pepsinut, I have some of those old patterns too and love them. You might try some of the sock yarns. Check what gauge they are suppose to work up to. I have a stash of an older yarn called Loisirs 139 by Phildar. It knits up to 30 stitches for 4 inches and I can get it to work on those patterns that call for 8 sts = 1 inch. I don’t know if they make that anymore either.
I love the fine yarns for baby things they work up so delicately. 
I hope you find some yarn that will work for you.
I recently discovered a site called Drop Designs that is Norwegian, I believe it is, but they have a lot of things translated into English. They have a lot of nice free patterns on their site, and they sell yarn as well, but none of it is that fine I noticed. You might like to check out their patterns though.
I have a similar problem. I bought some washable wool that is 28 stitches to 4 inches and that is a little big for my old patterns, and I haven’t found patterns for that gauge readily.