Help me find an eco toilet/wash-basin combo

[MamanCochon]

I'm sure I've seen one of these advertised in a magazine recently, but a quick Google didn't get me what I was looking for. It's a combined WC and washbasin where the waste water from the washbasin goes into the toilet cistern so you are using grey water to flush the toilet rather than potable water. It seemed like a really good idea and simpler than setting up a grey water system for the whole house. We have to redo our downstairs toilet soon and I wanted to show it to dp to see if I could persuade him.

Does anyone else know what I'm talking about? We're in the UK, by the way.

[MamanCochon]

I've found it myself! It's made by Roca and is called W+W. But I suspect it's quite expensive... so if anyone knows of a less expensive option that doesn't involve too much DIY please let me know.