The Kenwood DNX71XX series is a popular unit, you can easily get that for under 1200. It has DVD and NAV, a 6.95" screen. You'll need to decide whether you want a fold out screen or one integrated into the dash. Kenwood DNX71XX are 2din and has ample features, and is one of the few DD units that has RDS (Radio Data System). I really enjoy the stability of the in-dash screen, im rough on things and I didn't like the instability of the pop-out screen vs. the in dash. I believe you do get a larger screen on the single din units, and it integrates into the dash cleaner, looking less obvious that there is expensive gear in your car to take. You might also take into consideration what happens to the excess space if you get a single din, sometimes they make "pockets" out of the excess space. An 06 escape technically does not support a DD unit, but a little handiwork makes that no problem.
There are a few different guides here that might be able to help your decision... I'm having trouble searching the right keywords right now, I'll try tomorrow in a better frame of mind.