S.B.
I would look for a full size van/small bus type thing with an aisle down the middle. After six kids (4 in car/booster at one time), I cannot tell you how much I hated flipping seats back and forth, crawling over seats, etc to hook everyone it and out. Plus, the rule in my house was a child could NEVER unbelt themselves, even if they were capable of it, because they could do it when I was driving. If I could do it all over, I would have got the van! Also, you may find that you need help with taking the kids places (dr. appts, etc) and getting everyone in a mini-van isn't going to work.
I know that the vehicle(s) I am suggesting are not the nicest vehicles to look at or fun to drive, but when you get those babies home, you are going to totally forget about that :)
Good luck!