You have a great idea as there IS a need for clothing for those of us who are "not anorexic".  I am a size 8 bottom, size 14 top.  Using good fabric (no acrylic...Modal and tencel are wonderful new fabrics), with comfort and simplicity in the styling usually makes for a win-win combination.   Black is always slimming.   Keep away from empire waists...they only accentuate the tummy area.   Who wants to look pregnant when they aren't?   Designs that lightly skim over curves are much better with nothing too tight.   V- and scoop necks are good.   High necks are not.   Hope this helps in your decision to "go for it".