I have an idea but it may be a silly one so go easy on me here: Is there any reason why you couldn't take a coaster brake hub (also called back-pedal brakes here in New Zealand), make a lever arrangement to replace the sprocket, and run it as a front brake, perhaps with a cool rod-style linkage set-up? Is excessive free-wheeling bad for their internals? Has this already been done? Is this just really dumb? etc. etc.
