Here is the Stonco Incandescent Wall Light Open! As you can see I put in a 100watt GE bugbulb. The reflector is held on by two bolts and in a way it is self leveling.
Mr. Gull is right. They even sell very thin junction boxes made to be installed under the fixture if you can't install a standard 1½" box. I think Jace used one of those for the exit sign globe I sent him!
Or you can get an REALLY DEEP weather proof box and a 100 watt MV HX type ballast will fit in it!