That's a great location, wish I had noticed it when I mounted mine. Mine are secured via 3M Super Strength double-sided tape, the same that is used on Ventshades, on the door panel right underneath the tweeter area. Next time I have the panels off, I am going to move them to your location.I just installed a set of components in the front doors of my Taurus. I mounted my passive crossover almost in the middle of the door. There is one hole in the door there that I used to secure the crossover to the door. All you need to do for clearance is remove a portion of the foam padding from the inside of the door panel, and you are good to go!
Take your time, measure twice, think about it, measure again to confirm your plan of attack and go for it!
*NOTE: I used a nylon locking nut on the back of the short allen head screw that I used to mount the crossover to the door. I sourced the nuts/bolts that I used from my local Home Depot.
The hole that I used to mount the crossover I marked around it with a red box.