Spark, there was a huge amount of fooling around in all that nonsence I posted, I have never done anything even remotely close to that, but it sounded fun. Now for remodel work (by the way this is no messing around....) first I drill a tiny hole in the wall with my ever present 3/16 " tapcon bit (any bit would work, but I have that one in the pencil holder at at all times so it is handy.) and then I probe the wall with a piece of #14 solid to check for that there vent pipe first. If one is present in the way, I dap over the little bitty hole, and install two light fixtures instead of one or go the adjustable fixture housing method posted above.
