Alright, we had our test drive today, and they had a demo car sitting out for everyone to sit in and check out.
I measured for usable space, and not to the very limit assuming that you'll need to slide something in straight on. And, the seats in front were leaned back a bit like you probably would have them. With that being said - the measurement across was 40", 28.5" tall, and 11.5" deep, (there is some slop in this figure like I said - you could move the seats forward and crank them up more vertically, and pick up several more inches if needed.
I hope this helps.
Randy