I don't remember seeing this in another thread, but if I missed it, feel free to delete/merge this into the original.
I'm thinking a fully equipped Model S Signature will cost more than US $110K (before rebates). Here's my thinking:
300K Base model: $77,400
Special Paint: $ 2,500
Panorama Sunroof: $ 5,000
Upgraded Sound: $ 4,000
Upgraded Interior trim: $4,000
Sport Package: $20,000 (Same as Roadster. Think Air Suspension (+$5.5K) plus larger wheels (+$3K) plus upgraded tires (+$1.5K) plus motor/PEM ($10K)
Rear Jump Seats: $ 1,200
And, that's assuming there isn't a super-upgraded carbon fiber interior trim upgrade option, like there is in the Roadster. And that's not including delivery and taxes, etc.
At any rate, I'll be shocked if the top price is less than $100K.
A second question is: What's the cheapest Model S Signature possible? It seems the sunroof is optional (according to Design Studio), so I'd expect the jump seats to be optional. I could imagine the Sport package being required, although that be controversial. I think the upgraded interior and sound system will be standard on the Sigs. That still puts the Sig to be starting at $88K.