Here's my setup. The metal bracket is home made, and the light is a Magnic Light which takes the eddy current from the rear rim created by powerful magnets inside the light. No wires, no special attachments, just the light that you see. The supplied bracket mounts to the rear V-brake braze on (road and disk brake versions are available too), but I found that the light was hidden by the rack, fenders and pannier, so I mounted it further back like this. The biggest problem with it like this is that it is vulnerable to being knocked, you can't really see the tape in the picture that holds it together now.
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