rent bicycle for use throughout Japan

I live in Yokohama and will be traveling down to kyushu for summer holiday. Does anyone know if there's a place to rent a "quality" bicycle (with gears) for an extended period that I can take with me and bring back? Or even a shop in Kyushyu?

My experience is that the bicycles I can rent near the stations, when available, are mamachyari. I almost had a heart attack trying to climb the hills in Asuka, Nara last year on one. :)

i've had this problem over the years whilst travelling around japan and have never found somewhere economical to rent one from. Now i just go to a local Offhouse or used goods store and buy one, quite often you can find good bikes for less than renting one for a week.