For what it is worth, it seems to me others here think Model X will be more expensive than I think, so if my speculation is anything to go by, mine certainly isn't the most expensive speculation.
The only part where I've agreed pretty much without qualifiers with the said consensus is that the Model S base price goes up year by year (even quarter by quarter), and eventual Model X price will be relative to that. robby says in message #8 that part is something he didn't expect, so if that is the case, I think it is pretty safe bet by anyone's standards robby should prepare for base "2015" Model X to cost more than a base "2015" Model S 85. (Years used here just to indicate rough production time, not model year.)
I have actually been one of the few who optimistically give some chance of Model X actually only being "low single-digit percentages" more expensive than a non-AWD Model S 85, so in the Model S 85D pricing range starting price-wise, instead of 5-10% more expensive than Model S 85D which seems to be the consensus. I haven't seen that speculation from anyone else in this thread, so I guess I'm pretty much alone with some strain of belief in Elon Musk's Model X pricing word.
But even there, obviously, I am comparing 2015 prices of Model S and Model X, not 2012 or 2013 prices.
That said, I'm not actually betting on Model X costing around Model S 85D (or even a little less), just explained some scenarios where I think that could possibly be the case. Realistically I'm expecting Model X to be more expensive than Elon Musk optimistically has hinted to us in the past, but hoping I'm wrong of course.