same basic idea applies to glass windows, 2 planes representing the 2 surfaces, which today i just found is causing reflections to once again not work out right, since both planes on the glass have "glass" type shader, including reflections. 
con - reflections on both surfaces causes reflection wars, causing them to show reflections of eachother, along with screwing up lighting on them
pro - nice place to use SSS when double planes, and if refraction is set right, makes it look a lot more like windows :)

still need to fix reflections though -_-