At the moment I am driving a 4 door Toyota Corolla sedan and I fit three car seats across the back...two FF either side and the RF in the middle (they are all reversible car seats).

We have a Toyota Landcruiser Wagon 80 series, I love it to pieces! It has HEAPS of room with an extra 2 seats in the back if you need them. You can usually pick one up for about that price. Good luck car hunting i hope you find something!
That is what I am going to buy...an 8 seater