The Simple Life at Home

I like color. If you've been to my house, you'd know that. And I'm still pretty happy with the choices I made when we moved in - olive green for the family room and kitchen, dark red for the dining room, and the (non-master) bedrooms are each a different color. The one thing that I now regret is painting our guest room/playroom a dark peach color. Kind of a salmon, maybe. I want to lighten it up, but I don't want to have to do a coat of primer, plus two or more coats of a new color.

So, I'm wondering if there's any kind of glaze or sponge painting that I can do that will just be a quick, one-coat thing that will tone it done and brighten up the room some. It doesn't get much natural light and it's very over-stuffed with furniture so the room, plus it's the smallest room in the house to start with). Can anyone offer advice on what I can do? I know with sponge-painting you generally have the lighter color be the base, but does it work the other way around or would it be a disaster? A glaze would be nice if it would end up just being a pale peach, but I don't even know if there's something out there that would do that.

Anyone have any ideas?