I got the tape at my LBS, actually, but I think they ordered it from someplace called Iron Horse or something.
I wear a hiway worker vest when biking on roads, and have collected some bright orange or green shirts for bike trail day trips. My spouse likes her hunting vest, dayglo orange and lots of pockets. I am going to add some of my reflective cloth tape to it.
I carry lights even when I go out in the day, but i depend on bright, reflective clothing more than my blinkies.