I created my own pattern based off a wrap shirt that I purchased at a festival years ago. I don't have a specific pattern, but it was a pretty basic design (althought this will be hard to describe in words!)

The back was a rectangle shape: width across shoulders x length from neck to where you want it (plus a bit for hems etc.)

I prefer a slightly hourglass shape for arms; a big armpit leaves room for movement, narrowing down to slighlty larger than circumference at your elbows, opening back up to a wide wrist.

The front is the hardest to describe. at the shoulder, it should be narrow (a few inches or so) so that it meets at the edge of the back & arm and goes in as far as you like for coverage. At the bottom, it should be super-long!!!! Mine is long enough to cross in the front, wrap to the back & still have room to tie. At the outer edge it is a straight line, long enough to match up with the back, then the inner edge (the part that crosses over the chest) makes a slight curve across the chest part and continues out into a thin strip of fabric for the remainder of the lenght.

Hope this isn't too hard to visualize!! The front piece just needs to be reversed for L & R sides... you sew the shoulders together (R & L front pieces to the top edge of the back piece) open it up and lay out the arm piece and sew the armpits, then finally finish the arm into a tube and continue to attach the front & back at the sides! Waaa la!

I picked up Simplicity patter number 4483 and plan on just making the ties longer to make them wrap around the back. I heard someone else did this with another tie front pattern with good results, so I picked up this pattern when they were on sale for 99 cents.