Whenever I travel abroad I'm surprised how popular beverages in cans still can be - here cans lost in favor of bottles during the 1990s mostly.
What is the problem you see with cans, compared to bottles? Cans are recycled at least here, and their recycling is actually quite efficient and a good practice, better than e.g. recycling paper or plastic (source for this claim: http://www.youtube.com/watch?v=rExEVZlQia4#t=955
The personal reason for me to prefer cans to (glass) bottles is that cans weight less, make less noise and don't break as easily. And nowadays I don't even feel like a polluter, as aluminum cans are apparently recycled quite efficiently.
But going back to inefficient toilets? Why? I don't see any advantage in this and cannot understand any potential fascination with outdated and inefficient devices.
Finnish toilets actually seem something between the "waterless" German toilets, and those odd big bowls of water that American toilets seem to be.
This reminds me of the recent discussion here where people are bitching how the modern EU washing machines seem to use water too sparingly, causing the clothes still to be a bit dirty or leaving detergent residues to the clothes. I've had a bit similar experience, luckily my current washing machine has a button for "use extra water", which I use every damn time I wash clothes.
I got fed up sometime still seeing a bit of foam on my clothes, and also as I read some instructions how you should not put e.g. synthetic fabrics and towels to the machine at the same time, because then the machine will use too little water than would be needed for the towels (the washing machines are apparently so "smart" nowadays that if they detect synthetic fabrics in the machine, they use as little water as possible, which is then not enough for towels which soak up much more water). How about making the damn washing machines use enough water regardless?
Some things I don't understand from your question. Are you talking about cold water in baths? I usually do not bathe in cold water.
This is something that is apparently taught differently here, than in Germany. If you want to conserve water here, you are supposed to take a shower, not use a bathtub. Using the same shower water multiple times is obviously not that feasible.
But if one insists on using a bathtub, then I guess sharing the same water with many people is one repugnant way to try to conserve water. A bit like this: http://www.youtube.com/watch?v=maU30o2D6Dk#t=523
But there are regions that could use efficient water management technologies. Many regions in the US (Midwestern for example) use more water than is refilled by rain every year and consequently the ground water levels are going down. You don't need to be a prophete to predict severe problems coming up.
I still don't see why water-rich areas should conserve (cold) water. It won't help the less fortunate areas at all. I find it a bit similar thinking as if you'd have to build highly insulated houses with thick triple windows in Thailand, just because such way of building may be a good idea for cold Finnish winters. The Thai houses in general simply don't need to be as energy-efficient as Finnish houses.