Used is often cheap enough (craig's list), but you want new, I guess..
an IGH without a coaster brake and you can add a chain tensioner to a Vertical dropout frame.
you got any Bike shops around you? what do they sell ?
China and Taiwan make a lot of frames sold under various brand names, Pake one of them.
Last edited by fietsbob; 12-27-13 at 03:00 PM.