Ok, here's my attempt at a tut. Thanks to all of you for your nice comments -you have no idea how much they made my day!!!
There are 5 pieces in this top. Back, left front, right front, 1 strap (that acts as both shoulder straps and holds up the back) and the belt. The pieces are drawn somewhat to scale.
I used my duct tape dressform A LOT I don't do any measuring, just use the dressform to approximate lengths, widths and whatnot.
STRAPS: I made a tube of fabric about 1.5'' wide to run from my outer ribs about 2'' below my armpit, over my shoulder, to the middle of my upper back where I wanted the top of the back to hit, over the other shoulder and ending at the other side rib. Make the ends of the tube as neat as possible as they'll be visible.
BACK: I made the back long enough to hit around hip-height (plus 2'' of seam allowance.) Since I pleated the top of the back, I added about 5'' extra width to the back. I hemmed the bottom, and pleated the top while attaching it to the strap.
FRONT PIECES: These are basically huge triangles that are a bit more rounded at the top to give a sweetheart neckline instead of a V-neck. I added about 6'' of length past hip height since I did a lot of pleating. The top pieces are pleated from their top hem until about midrib. From there, I just attached the front, back and straps. See bizarre drawing below for an image. She's hyperextending her arm the wrong way so you can see the side. The straps end right below the boobs. I just turned them under and sewed em down so they looked neat.
I sewed everything together and left the 2 front pieces flapping open. I made a belt (a 45 tube about 2 wide) and used the belt to overlap the pieces and hold em shut. I then eyeballed the bottoms of the front pieces, cut them to hip height and hemmed them.
This is my first tut, so I apologize for anything that doesn't make sense. Please let me know if you have questions. And if you make a version of this top, I'd love to see it!