Originally Posted by
laura*
You can't find one because such a hub is not possible. A coaster brake requires that you apply force by pedaling backwards. A rear derailleur makes that impossible - instead of applying the brake, the derailleur cage would rotate.
Yes, but Bullseye (aka Roger Durham, the hubs & cranks manufacturer) made a one-way clutch & lever mechanism that pulled a cable when the cranks were backpedaled. This activated the brake (or brakes). This is rarely seen- it's usually a very custom job.
My friend Jane has one on her hand-and-foot powered recumbent:
http://www.ohpv.org/events/albums/jf...s/IMAG0238.htm . She's using a Rohloff hub, but it could just as easily be a derailleur setup.