jph- I just want to put a reflector on that spot and I use a light on my seat post. I haven't done the reflector yet but I am thinking that I will just get some accessory cord and tie it on. The reflector is nice and light and think cord would work just fine. Also, I know that The Touring Store sells some lights that attach to either a 50mm or 80mm mount. Maybe not the brand you're after, though.

I ordered the PB SpeedEZ fenders and my LBS should be getting them sometime tomorrow. I will let you know how well they go on and stay on once they are on.