I would recommend Energy Systems and Design at microhydropower.com, because I used their products most successfully, and also I sold their turbines and found them to be excellent.
I also used and sold control equipment from Thompson and Howe Energy Systems of Kimberly BC. Here's a link to their address and catalog, they still don't operate a website as such despite their many achievements. They have always had plenty of business from word of mouth and don't advertise much. They make a truly excellent load controller, used with larger AC systems to put every bit of energy generated to use somewhere in the system and incidentally hold the speed, voltage and current within narrow limits despite changing loads. A great machine:
http://www.smallhydropower.com/thes.html
The Powerpal line of equipment is very cleverly engineered, and offers battery and inverter free AC systems down to 200 watts in output with as little as five feet of head.
As you can see from the case studies in Serious Microhydro: Water Power Solutions from the Experts, even such a small system would do many important things to contribute to a high standard of living. After a certain point, most of the benefits of systems larger than 200 watts can be provided with other technologies. It's just that you can hardly charge up your laptop with propane...
The real issue with microhydro project development is to get someone in your area with experience, in order to deliver a good running system with the budget available...
cheers,
Scotty
