Has anyone had any luck with mounting a light to a gas block rail?

I currently have this on my AR:
http://www.pkfirearms.com/product_im...RRA-FUFS-4.jpg

I'd love to get a light there, but the problem is that there is only about 1/2 inch of clearance between the edge of the rail, and the end of my floating quad rail. I'd prefer a "real" sized weapon light with a remote pressure switch, but it looks like I'm going to be looking at a pistol sized lights, which are mostly plastic and will probably melt.

I suppose I could always look at extending the rail, but didn't know if there were other options I'm not finding.