Actually back in the day they did have a machine that the bobbin thread came off a spool.
http://community.stretcher.com/blogs...g-machine.aspx
photos
http://home-and-garden.webshots.com/...35286911OBEqmC
http://home-and-garden.webshots.com/...35286911OBEqmC
Just look for National two spool if you are interested in more info