...Or a standard folder with a new IGH wheel & Surly Singleator. Might get you close. A Dahon SUV D6 is cheap enough a wheel build might not put you over by much.

Edit: An Origami Cobra would definitely do it. Just run full length housing from the shifter to the hub.

Act fast! So far as I know Shimano discontinued the 8 speed coaster brake hub.