i've seen this top and thimblebug has it right. the only difference i saw was that the neckline had a very soft facing becuase when you get down to the 'v' of the neckline, you have to snip the fabric to spread it to fit and that invites frays or tears.
i saw this in provincetown in one of those little boutique shops where they make and sell easy to make, one size fits ( almost ) all, wonderful indian (or other interesting) fabric garments. they also sold things like long pieces of fabric (long, long, long ) that you wrap around yourself, throw it over one shoulder and call it a dress (?). mucho dinero. peruvian tote bags, etc. you get the picture.
actually, because of the fabric, very beautiful things and very pricey. nothing you can't make at home though, with our fabric, if you're selective.
also, picture a front-wrap straight-line dress. now picture that the front has a very wide overlap. the overlap has an extra armhole. when you put your arm through this extra hole, the front wrap stays in place. because the wrap is so wide, it covers well. one arm goes through 2 armholes. can you see that? that's from that same store. easy and clever, and one size fits (almost ) all. as they say on menus, $$$$$.