[ttraub]

A reasonable compromise might be one of the high efficiency shower heads that have been around for decades, e.g. the Delta. These gadgets have been around since at least the 1980s, come with an on-off switch to shut off the H2O while you soap down, and cut the flow while increasing the intensity. It's almost ideal. In fact I need to make a trip to the hardware store and pick up a couple to replace the lame heads in our two bathrooms. These types of heads simulate the mister experience but also spray the water quite intensely, almost painfully, if that makes any sense :)

Regarding energy use, it seems to me that solar thermal is the way to go; you can keep your tank pretty hot during the day and if it's properly insulated, should minimize energy use at night. If you're showering early in the morning, though, you'll probably be burning some fossil fuel, but if you can time your showers to be mid-day or evening, would be optimal.

In Phoenix, probably every fifth house has solar hot water; it just makes economic sense. When we traveled in the Middle East (mainly Israel), every house and apartment building seemed to have solar hot water. If it makes economic sense (and the tax credit also helps), people will adopt it. I'd be reluctant to support some kind of mandated regulatory approach that forces a less pleasant shower experience on everyone; as others here have mentioned, the shower is one of life's great luxuries.