It's pretty clear that the "bulb" depicted in the wall relief at Dendera is not a sarcophagus lid. No one on this thread would disagree with that conclusion except for R.Fusniak. So, we do not have to further debate the shape of the "bulb."
If R. Fusniak had any substantial proof that the "bulb" was a sarcophagus lid, surely he would have presented it to the board by now, particularly as he has been encouraged to do so on more than one occasion, as well as the fact that he indicated that his source for his claim, David Rohl, was a "personal friend," and that David Rohl was of the opinion that the "bulb" was a sarcophagus lid.
As Frank D. pointed out, according to him, Rohl has not even read the accompanying texts, so, we can move on from there. Most textual evidence seems to point towards the "bulb" being a shrine object associated with the creation myth and symbolic of the sun/sky relationship. OK. Maybe, so. But what is the djed pillar doing there? Is there still some unknown technology symbolized here?