I read that the xB has 3-point anchor seat belts for all five seating positions.

But I looked on the "zoom pictures" on scion.com and I can't find the middle seatbelt in the rear, is there one?! Was it just missing from the prototype they used for the pics? Help!

Yes. It's right on the seat it self. Between the right headrest and the middle seat headrest. Use the 360 degree on scion.com (interior pic)

the Zoom pics are not updated.

its there, but it is removable.