I don't know if this will work, but I'm thinking it could be as simple as a screw, or at worst a screw, a washer, and a screw adapter.
It would depend on the kind of belt clip you have on your light, but many have holes in them. If it's just the right size to let a 1/4 screw through, then you could just attach it by screwing the clip to the tripod hole in the bottom.
Worst case is the hole is too small to let a 1/4 screw thru. Then just use a smaller screw. Put the washer thru the screw, put those things thru the clip, and then use a screw adapter to screw it to the bottom of the camera.
I don't know if it would work well, and it would probably scratch things up, but I was just daydreaming.