I certainly wouldn't like to sleep on that mattress!! I think the stain that I used was from spilt tea, it looks much nastier post photoshop though!!
I think the sink is fine, it's just that the underside of the bowl is in shade. I've attached a wire of it to illustrate. I've been toying with putting a lamp in that corner of the room and I think that I will now!!
I know what you mean about the bedside lamp being too bright on the cabinet, it's because it only has the default lambert on it at the moment, once I make a shader for it that problem will be solved.
Take it easy,