Before the kid was born, my wife bought some of these Miki-House side-tie pajama/onesie-like things from Akachan Honpo, the Babies R Us of Japan. It was the interesting shape that caught her eye, I think.
They're cut flat in this body-shape, with snaps on the legs, and the seams are on the outside away from a baby's skin. It worked pretty well although we figured out pretty quickly that these weren't straight subsitutes for footie PJ's or Onesies; there aren't snaps all the way across the crotch, and so the kid's diaper was all bulging out and flying free.
In fact, they made look like a tanuki, the Japanese racoon-dog god of gluttony, whose giant-nutted statues stand at the doorways of many Japanese homes and restaurants. Ultimately, not the image I had in mind for my little princess.
Miki-House combi underwear 3-pack [mikihouse]
Akachan Honpo [in japanese only]
Tanuki: the Japanese god of gluttony, boozing, and restauranteurs [onmark]