I'm using one now and it has worked great! They're good for keeping the draft out because they're nice and tall and I haven't had any issues with them getting dangerously hot or anything. My only worry was the metal wire fencing I used for the top... I was afraid the heat lamp would heat it up super hot, but as it turns out it only gets moderately warm.
I bought the biggest one I could find, cut out the center area and bolted some wire fencing onto the top with nuts, bolts, and washers. The fencing is the metal mesh kind, the squares are about 1/4" I'd guess. I cut it to fit and mounted the fencing material on the top so that there were no sharp edges underneath for the babies to hurt themselves on when they start jumping & flying. Mine also has handles that lock the top on, which I wanted so that my cat can't get at them if she gets in their room.
I'm at work now but I will take a picture when I get home and post it as a reference.