I live in Gifu-ken, which is about 2 hours by train from Osaka. Living in Osaka, you should have no problem finding fellow crafters, I would think. I live in the suburbs, so there aren't any craft groups around here, but I initiated my own, very local group, mostly with the JET community nearby. (I'm here with the JET Program.)
Ooh, I work in Gifu-shi (though I live in Aichi). No I don't know about any craft groups either (though you could probably find classes for traditional Japanese crafts).
As to supplies - its amazing what you can pick up at Daiso (100-yen shop).