Every few years I need to update this "innovations" entry as things just keep getting better. Not all "gadgets" to save water work, and not all toilets actually flush clean. For details on the comparative performance of low flow toilets that do work, check out the MaP rating system, which is begining to appear on boxes on the store shelves.
Back in early 2000 we showed a prototype of a completely different type of toilet flush mechanism and now that toilet is on the market and performing well. Basically it has a tip bucket in the tank that fills up with the 6 litres of water required for a low flow toilet. When you tip the bucket, the water falls from the full height of the tank, giving it a good force to flush out the toilet. In fact the design allows for the elimination of several restrictive passageways common in most toilets. There is never any condensation on the tank because the water only touches the tank itself when it is flushed.
In 2005 I installed an Australian Caroma wash down dual flush toilet that was leading the evolution of toilets -- and this one is still working in my own home. Unfortunately in 2018 the Australians are have difficulty servicing their toilets in North America. Probably better to avoid Caroma today -- a wonderful toilet but next to no service.
The Canadian guys who made the flapperless toilet were back to the drawing boards and have leveraged air displacement from filling the tank to push a limited quantity of water up in the bowl for a larger water surface and then again using air to help initiate the syphon so that now what used to be a extra low flush for liquid matter now can clear solid waste with just 3 liters -- and that is proved by the MaP testing! They call it the Proficiency ultra high 3 litre efficency toilet.