One thing people who are against rooftops might have not considered, is that if you build a house with ideas in mind, incorporating renewable energy ideas into the design of a house may be easier, and work better than adding to a current structure.
For instance, since I am building a straw bale house where the walls are 22" thick, I might be able to incorporate tower poles inside the walls that do not actually attach to the steel structure itself and go right into the ground. it would be cushioned by the straw on the inside of the wall. Since the hard agstone is only about 3" thick and the inside is just empty space, free standing turbine poles could run the length of the structure. The best of everything. Less wire length to the batteries, wiring terminal, ect...Guy wires could still be eliminated and the turbine could still be mounted high enough to get above the turbulence.
But I would not want my agstone cracking all the time and have to do that much added maintenance as there will be enough already having to whitewash it every year.
But I guess one could use cement stucco instead on that wall and not worry about it.
Of course one could do wind tunnel tests and make a roof design that would actually increase the wind velocity as it moves across the surface of the roof. Utilizing a complete 360 degree wrap around porch, the pitch of the roof could be kept to a very low profile on the outside parameter. As long as your house in not very tall say under 20 feet tall at the highest peak on the roof and about 7 feet around the porch area, landscaping could be done to deflect any ground winds to flow smoothly over the top of your house.
These are just thoughts of theory that I have been tossing around.
I would want at least 4 turbines on the roof producing 2k+ watts each.
All of this requires more brain power than I have....
so I think the easiest is to do what others have suggested and just build a separate tower.
Murlin teh open to suggestions...keep 'em comming
thanks