In the next couple of years we intend to remodel the back of the house, put
in a downstairs shower and toilet, and do various other things.

This will include replacing the current boiler and doing something with the
hopeless hot water system - at the moment you have to run the water for a
couple of minutes before anything approaching hot water comes through.

Obvious choice is a combi boiler situated close to the kitchen and bathroom
to give short pipe runs and on demand hot water.

However this is also an opportunity to 'go green' with for example a heat
store, solar water heating on the roof, a wood pellet boiler.
This also gives the option of adding other heat sources such as a solid fuel
stove with back boiler to heat water in the winter.
In this case the pipe runs are likely to be longer but good lagging and a
pump may help the 'instant hot water' requirement.

Is this a feasible option?
It looks expensive compared to a combi boiler - at least three major
components at least compared with one - and the financial (as opposed to
moral) payback may be unrealisitically long.

Has anyone gone down this route?

Is anyone contemplating it?

For us it will be a 'now or never' thing as once the house is done we have
no intention of mucking about with it for some considerable time.

Cheers

Dave R