This company offers a complete manual clothes washing system. The parts are sold as either a complete kit or individually.
http://www.bestdryingrack.com/hand-wringer-washer.htmlMy considerations:
1) The wringer mechanism has wooden (maple) bearings. I don't know how long these may last.
2) The wringer rollers are rubber coated and this may be impossible to replace, someday. They might be replaceable with hand made wooden rollers.
[EDIT] pour spelink