Old Navy has some nice ones. The sizing for you is probably an XS and Old Navy offers those options. Target also has some nice one pieces. You're probably an XS in Target too And if all else fails, you could buy a tankini! It's just like a one piece but separated into two pieces. Try finding them at target. rel ALL|women's clothing
No, it's not that skinny girls don't wear one piece they do. I think that you must go and look for it in different stores. If you do not find it then you can go to the tailor and order it by giving your measurements to the tailor.
Try monokinis they cover the midsection and look Awesome :3
We NEED to see dat mid-section. However if you insist you should go to kidz store they have size ones and zeroes that will fit you and we don't NEED to see dem kidz mid sections so they will have dat one piece at da kidz section.