Combining a sink with a toilet in the interest of the environment isn't a new idea, but remember the disastrous results from last time?
W+W is a new sink+toilet combo that could fit in any contemporary bathroom, and it's a real product.
The premise is simple if you haven't heard it before: The "grey water" from sink-based activities like hand washing is captured, filtered (for bacteria and odor) and stored within the toilet cistern. Whenever you flush the toilet, this gently used water (that need not be completely pure) washes your worst offenses away.
If there's not enough grey water to go around, no worries. The toilet is also connected to the main water line.
However, in W+W's case, all this eco style comes with a price. This toilet+sink runs over $4000 in the UK. For that much, one can plant a lot equally nice-looking trees or convince themselves to eat less fiber. [Dezeen]