The US distributor for the spoke wrench is Wheel Fanatyk. It is a nice wrench, grabbing the nipple well and optimizing the use of the space that you have by a spoke. To make that emergency spoke, you just cut a spoke and combine the pieces with screw wire connectors from a terminal block. The person on the German list who developed that design said that the connection lasted fine for several years on one of his bikes, as he did not bother to replace the spoke there. Note that in the repair, you keep one or other piece of the original spoke, depending on how it broke.