Thanks. I have asked this because a friend has shown me some quite beautiful and cheap singlespeed bikes such as:
http://imbikes.com/bicicletas/bicicletas-fixed/kamikaze-azul-pinon-fijolibre-con-frenos-473.html
One problem is the dropout is 120mm, so theoretically a 135mm standard motor could not fit. But a friend has told me he can reduce the size of a Q100H to 128mm, and stretching a bit the steel would allow to fit that motor. He has done that before with another singlespeed frame, and it worked.
The main issue, of course, is again where do you put a controller and a battery. With a BBS-01, the controller would be hidden, so the "only" problem would be the battery. But as you say, a BBS-01 would not make sense with a singlespeed.
Has anybody tried to electrify a singlespeed? It seems an interesting exercise.
