Ohmighod, that is exactly what I need for my planned additional half-bath under the stairs. There isn't a lot of room, and I've been trying to figure out where you could put the sink. I'd actually come up with an idea like this, but without the water-saving aspect. It's perfect. Now if only I can find one stateside when I get to the point of actually doing the addition. (The projected date is rather vague and depends on the availability of funds.)