it depends if you want a full sized or compact suv- we have an escallade esv (full length)- we get 14 mph (not excellent but better that what you are currently getting wo loosing the size). before we had an escape and I was gettng about 20 mpg in that but you loose the 3rd row seating.
I have a Saturn Vue Hybrid. It averages 28 to 30 mpg. And I LOVE EVERYTHING ABOUT IT. The gas mileage is a bonus.
not sure any suv gets good gas mileage. We thought ours would be better but no luck. We have a 2004 Chevy Trailblazer Extended which has seating for 7 passengers. It gets 10 mpg around town but have averaged 16-20 highway on trips if it's not too windy. It is a V-6 with all wheel/4 wheel drive. It is very comfortable, even that 3rd row has good leg room and my teenagers fight over the 3rd row lol. The only reason we have kept it is the comfort and the fact that suv's have lost their value so much that when we bought it we thought we got a good deal on it because the price we paid was thousands lower than the blue book value but a year later the SUV's dropped a lot in value so we are stuck with paying a lot more than it's worth to pay it off so we decided to continue paying the payments and keep it until it dies which we do with our vehicles anyway. We have a truck with over 250,000 and a car with 206,000 miles on them and they are still running strong and we bought them brand new.
My friend has the new Chevy Equinox and she loves it and says it gets great gas mileage and she had a GMC Envoy before getting this one. I think the Equinox averages 28-35 mpg. Hers doesn't have 4 wheel drive which most vehicles with 4x4 use more gas.