Set your water heater lower. Like: make sure it's above 120 at all times (130+ preferably) to prevent legionnaire's, but 140 is PLENTY for most home uses. And it means you get a bigger range to move your mixer taps to.
Actually at household water pressures, water's boiling point is somewhere from 140-160°C, so it's actually somewhat plausible. I'm sure some less heat tolerant stuff would have to be upgraded, but the system's total pressure would be about the same (with the added danger that the consequence of a pressure failure would be a steam explosion instead of a leak).
And of course turning your faucet on hot would now blast out a stream of boiling water propelled by superheated steam, which is probably less than ideal.
Came to say the same thing. Not sure why people want boiling water on tap. If I need to boil water I use my kettle, and save money by not heating a tank of water to near boil all day.