You may have to get a dress altered to add the corset back. A friend was able to get this done using the material taken from shortening the dress. Very pretty!
Try Priscilla of Boston, Jim Hjelm, Mon Cheri... because this is so simple (my taste as well), you may also want to consider looking at bridesmaids' dresses that come in white. Bill Levkoff has a few styles like this. Good luck!
If you aren't completely set on the corset back, David's Bridal has a few dresses like this that are fully overlaid with lace- very simple and elegant yet pretty. I imagine it might be tricky to add the corset, though. Check out Style: CT2406