I saw one launched with a C6-3 strapped underneath, towards the nose. It actually worked quite well, climbing to about 40 feet and looping once, after the motor burned out it glided for about 20 seconds.
There's a smaller one, with about a 16" wingspan, that I bet would work great as a boost glider on a longer rocket. You'd have to glue the wings on though, I'm sure.
I have successfully converted the small Guillow's foam space shuttle to a boost glider, with nice long glide times. I have another one which I installed micro-RC gear in, but I've made only one flight so far, which was not successful (too much elevon deflection, snap rolled, barely recovered before boinking a pickup truck.)