Is it shockingly real or is it just an optical illusion?
There are another pair of cup holders, right on the rear seats as test drove by GigaOm!!!
At about 5:19 into the video:
This was a prototype some actually saw way back during the GetAmped tour, a photo of it is here:
... but no word yet if it's coming to market. Also, looks good but loses that middle seat, however, there's a hint that an alternate version for rear of Model S might be in the works too, just read this: