I agree with Cincy'sMom. I have two mini-vans for work, and I pick up a LOT of dogs in them. I have taken the back seats out and put in crates, and I can haul 20+ dogs in them. Of course, unless you own a grooming shop, this is probably overkill. However, I can take all ten of my dogs out for a drive, as well.

When I had only four dogs (a much more reasonable number!) I had a Geo Prism. Great car ... and the back of the back seat folded down, either the whole seat, or one side. This opened up a huge area, the trunk and the flattened back seat. (Is this making sense?) So, if you don't want to go the mini van/SUV route, you can always get mid-sized car with a folding backseat and have tons of room for pooches or people.