Just to update this thread, I sold my Frontier this week and now have cash available to purchase a new family rig. We went and looked at cars today. We brought our daughter along as well as her current car seat and the car seat her new baby sister will ride in for the first year or so of her life. I wanted to pass on my observations for anyone in the same boat that I am in with two kids in rear facing car seats. We tested them in a 2004 Suburban, 2005 Armada, and 2005 Expedition.
Suburban - We ruled this one out before even driving it due to the way the car seats fit in it. On the Armada and Expedition, the second row is made up of three sections. On the Suburban, it is a 60-40 split or something close to that. Unfortunately, the 40 side is behind the passenger seat. This means that if you want to have 2 car seats in the middle seat and still access the third row, you have to have a seat behind the drivers seat. The Suburban was the least well laid out of the three and in order to have the seat behind the drivers seat, I had to have the drivers seat slide forward more than I was comfortable with. The actual seat itself was the most comfortable of the three however. The third row was also the hardest to get into of the three. The Suburban felt like it had the least amount of cabin space of the three. The main advantage to the Suburban was if you need to have passengers in the third row, it has by far the most amount of cargo space available.
Armada - The Armada had plenty of space in the second row for the two car seats and could have the front row all the back and still fit the seats. It was also easy to access the third row. The third row was the worst of the three however. I found the front driver's seat to be very comfortable, but the placement of the armrest was very awkward. The armrest was not comfortable to me, but the center console was not at a level where I could comfortably rest my arm on it either. We only test drove the Armada and the Expedition. In terms of driving, I would give a slight edge to the Armada in quickness and handling. The steering is a bit tighter and feels like you are driving a sportier vehicle. We only belted in the car seat in the middle, but I did find that it was more difficult to get it sitting properly due to the placement of the middle seat belt. This might only be particular to our car seat and other models might be better.
Expedition - Like the Armada, there was a ton of room in the Expedition in the second row. You could have both front seats all the way back and still be fine with the car seats in. We strapped one car seat into the middle ,and it did sit much better and was easier with the seat belt than in the Armada. The third row was the easiest to access and by far the most comfortable for an adult. It did drive nice and had good acceleration. It was little slower than the Armada, but there wasn't a huge difference. The driver's seat was comfortable as well and the center console made for a good armrest. One small thing it had that was a nice feature was a drop down mirror on the ceiling so the front passengers could view what was happening in the rest of the car which the other two vehicles did not have. Price wise, the Expedition was also the cheapest of the three even though it had 25K fewer miles. We felt like the Expedition would meet our needs the best and be the best family vehicle for us. I know I was leaning that way to start, but did feel like I gave the other vehicles a fair shot. Unfortunately, I was not able to test a Sequoia as well. Now we just have to decide if we want to go with one of the available Expeditions in town or wait until a better deal comes along.
I hope this might be of some help to others who have the same considerations as my family.