The Model X signature edition deposit is $40K, the regular deposit is $5K; the two together may be where you got $45K. There is no reason the model X would be cheaper than the Model S; most of its versions have two motors instead of one in the S, and it likely has a bigger battery. That's not to say it won't be the price of the current model S, but no way it will be of a contemporary one.
The base model will have just one motor though, and the batteries are actually the same as Model S (60kWh or 85kWh). Given that they've had time to refine their manufacturing techniques and such, it could be cheaper than Model S.
However I agree that $45k is likely incorrect, and in practice it's hard to imagine they'd make it much cheaper than Model S, if at all.
