Take this with a grain of salt as I have no experience with dealing with commerical companies. There are several of the big companies(GE Vestas Siemens etc) that made 5 to 50 kw units in the past. Many of those are at the end of their warranty/lifespan for windfarm use and may be available for purchase if you can find the right folks at the right time. They seem to be a pretty good deal if you can do much of the upkeep on them yourself. These companies probably do not make this size turbines anymore as most are now making 500 kw and up. California may be the best place to look for these units as they were the lead in windfarms for many years and I have read that many of their older units are being replaced with new and bigger turbines. The same should be true in many of the older wind farms around the USA.
As far as buying one from any of the ebay internet etc sellers I would go with a buyer beware and you tend to get what you pay for attitude.
I'll plug our hosts and say that most of the folks who have bought a unit from them seem very happy.
Now one last thing what do you mean by 10 to 35 kw per hr? For turbine size kw is a rating based on an instantaneous (more or less) reading @ a certain wind speed usually the highest wind speed before furling. The hour part is just how long the wind blew at a speed to produce that rate. There is no standard really for posting ratings and you have to do the math to compare units especially when looking at the wind speed range and electric production. Cut in to furling and power curves.
Finis
