Oh, I wish! I will say that I feel like the things I've knit with pearl cotton embroidery thread are a smidge softer/less stiff than the things I've knitted with crochet cotton, but not massively so. I have been curious about trying Knitpicks Curio, since a lot of people seem to knit actual garments out of it instead of just doilies, but haven't actually gotten around to acquiring any yet.

It's not cotton at all, but for a fine yarn with a nice sheen, Knitpicks Gloss (merino/silk) is very pretty and VERY soft. I have some of that to hand and would be happy to send you a swatch if you want.