You might manage that kind of mileage in a Prius, and certainly could in an Insight. Frankly 6-7 miles each trip is not enough to warm any car up fully...so no matter what you drive you should expect less than optimal economy. As to whether the Escape Hybrid is significantly more environmentally friendly than a conventional car, it really depends what car you are comparing it to. There are a number of conventional cars that are nearly as clean under the right conditions, but there are a whole lot more that are far dirtier.

A pure electric vehicle would probably be ideal for your commute, especially if you're using a different vehicle for your longer distance drives.