That might take sales away from the X, not sure they'd announce them together.
As to G3 technology, as I posted on SA, Tesla could do around a 45kWh pack today using the 3.4ah Panasonic cells already available. With a smaller frontal area and if they get an even better coefficient of drag than the S it could hit 225 wh/mi to just maybe squeak out a 200 mile range, but definitely 180 miles. (Roadster hit 220 wh/mi for the 240 mile range). Smaller motor, smaller inverter, lighter battery pack, shorter and narrower wheelbase would all add up to a much lighter and less expensive vehicle. Using Musk Math the stripped down base model could be priced around $45K and come in the $30K's after rebates.
I don't think they are going to move the G3 up by much but I don't think technology is the barrier.