I really like the suggestion of taking a carseat with you when you shop, it may seem silly but it can make a huge difference. I had a Honda Civic up until last year, DD is 3.5 now. I won't lie, it was a pain. DH is tall so he couldn't fit in the car if she was in it so we drove his truck as a family. Getting that low and lugging the seat out got old (and heavy) and then when I finally moved her to the side since the convertible seat wouldn't fit in the middle I would occasionally bump her head because I couldn't see down that low.
We lived in Chicago for a year through work and had a string of rental cars that they paid for so it was great to get to try some out, we had a Dodge Nitro and a Hyundai Santa Fe and those were better for reaching in with her. We just bought an Acadia about a year ago and I love it. I know you said you don't like big cars so it's probably too big- but we also drove the Chevy Equinox and the GMC Terrain (pretty much the same car) and they both have middle seats that slide forward/back which held with the size of your carseats. They also both have a good amount of storage in the back, but don't 'feel' like a big car.