Sith Tattoo
I'd have to go back and study my videos, but I don't recall the markings being identical. I could see the ceilings of the dwellings being similar due to a common "interior design" scheme on Tatoonine, but the Tattoo must be a mere coincedence. Did the Cantina in ep 4 or Watto's shop have ceiling markings ?
Re: Sith Tattoo
I think it was too dark in the Cantina to see any markings and Watto's shop has a very high ceiling so you can't actually see it.
As for Anakin's home, I just read one of my Star Wars Magazines (UK version) and John Knoll did indeed say that it is just coincidence that the markings look like Maul. He also mentioned a lot of other false rumours like the one about Indiana Jones appearing in the Podrace crowd and C-3PO having his coverings on while standing in the background of a scene.
Re: Sith Tattoo
I don't actually see why some people think they actually the same. I don't think the markings on the ceiling look anything like Darth Maul's tatoos. Besides, I would presume that the ceiling for the set was actually made quite a long time before the final design for Maul's face was finished.