ljmarsh asks:I want to know what is the most effective and green product for insulating an existing pre-1950 brick 2-storey home, to a degree of effectiveness that would make the home ready for solar heating or geothermal?

Try (Biobased) http://www.biobased.net/faq.php they create an insulating foam product that expands by a factor of 100 here is their about clip:

Polyurethane spray foam has been around for more than 30 years. BioBased® Insulation began operation in 2003 with the commitment to help create a healthier, more durable, energy efficient and environmentally responsible insulation. Our focus as a company is to develop a family of sustainable building products that perform well and benefit the environment.