Here is a site you might find interesting. I have spoken at length with Gordon Howell, the engineer who spearheaded the project. Solar really is v. expensive, but it was the last step to net zero. he is approachable if you have any questions. He did have a problem with the vampire draw of UPB, etc. You might want to look at these:
http://www.enocean.com/en/home/
No power required!
Personally I have 2 UPB systems with HAL/Cinemar hybrid control. I now use an iPad for touch screen control of everything ( v. high WAF!). Main Lobby can control the Lutron shades very precisely. Couldn't get Hunter-Douglas to work, and the installer did one job with Somphy and never again after the ease of the Lutron. Use Russound for audio with hardwired speakers. Avatrix matrix swithcher for video, all controlled by touch screens.
Elk M1 security interfaces with the HAL/Cinemar system- some UPB commands are issued directly by the ELK, eg lights in response to motion sensors.
Speaking of motion sensors, have a look at this:
http://nitrogen.posterous.com/ascii-art-kinect-hacks#whatsnext
The system requires PC, another power draw ideologically, but possibly justified by practicality. The system has saves the house several times when the boiler has failed- yes, i am on the frozen steppes of North America-Edmonton Alberta. Still have 2 feet of snow in the back yard and it's snowing again today...
I used ICF in one application and SIP's in another. Used IR cameras to monitor installation to ensure insulation was tight. Windows are an issue, but I decided that is where I am willing to spend a bit of energy to get enough natural light inside.
I get an email and text message about status and alerts if the temp is too low or the sump is too full, etc. The system handles telephony as well.
The system cost is a consideration. I think my cost is less than 20% of an equivalent Crestron.
I have both places wired and plumbed for solar heat and power with the connections stubbed off in the ceiling, waiting until utility cost justify it.
Universal design was implemented so that they can carry me out of the place at the end. Approaches are graded for easy access, doors a little wider, no curb in the shower, too name a few. Can't find my usual reference to this, but a complete example can be seen here- http://www.quadomated.com/
For example, while I have no need of it now, I have designed the space and placed hangars inside the walls for an elevator in one house ( a 2 story) and designed the stairs in the basement of the other- a bungalow- to accommodate one of those stairlift devices. There are a lot of little things in construction phase that become big and expensive if you have to retrofit.
I believe you are on the right track with your reasoning and assessment of the future. We have to think globally but act locally, and our own personal space is part of that.
Hope you have a blog so we can track progress!
bob