I suppose. I was thinking that a truck-based full-size SUV might offer a different set of capabilities than an X and therefore appeal to a different set of buyers (e.g. more space? less luxurious?). And if the base price of the truck is supposed to be around 50k, maybe it would offer a less expensive option that's roomier than the Y, but more bare-bones than the X. But I guess it would crowd the lineup a lot, and probably unnecessarily. Just a thought.
I think the overlap with Y and X would be self-defeating. It may also be that the cabin on the Truck is sufficient for SUVness. At one point Elon was talking of seating 6. Add a cover to the bed and you have a lot of SUVish capability.