There are tons of great construction companies and general contractors doing green work. Some are better suited to larger projects, some do housing developments, and some do remodels. I like remodeling, so long as strict attention is paid to improving the energy envelope of the existing structure, because using current housing structures creates less of a demand for building materials than building from the ground up. This means less raw materials are used, less carbon is used to ship materials to a building site and less waste is created. The USGBC (United States Green Building Council) along with stakeholders including the ASID (American Society of Interior Designers) just released draft guidelines on how to accomplish a green remodel. If you happen to be in the area of Menlo Park, Ca, check out the work of Arends Construction. The photo shows a custom concrete countertop that Ken Arends made for a client using the broken window glass from the single pane windows that had to be removed in the remodel. That is taking green thinking one step further, don't ship your remodeling waste off site, use it in the project!