When a single soap that can do all that comes along, I'll be first in line to buy it. That being said, I really like the Likas Papaya soap from the Philippines. It doesn't claim (on the box) to lighten, but users seem to think it does. Go to Jose's thread 'my gift to those with dark marks..." or something like that & look at the photos he's posted of his results.
In my case, I find it is an excellent exfoliant & it leaves the skin super clean to better absorb the creams. It rinses clean leaving no residue, oily moisturizers or cloying scent. Not only that; it is cheap! So, if you buy it, decide you don't like it & toss it, you've not lost much.