Of course it can be done. You can install a toilet on your roof if you really want to.
The big concern would be, is the dealer going to get it right? They are going to be drilling holes through your roof. Are they going to touch up the paint where the holes are so you don't get rust later on? Or are they going to blob some silicone on there. WIll it be water tight 3 years from now?
The dealer should be able to get the parts.
Do you need the function of roof racks? Or just like the look?
I personally like my EX to look a little more "car" than SUV. So I don't have the roof racks. But, that is all just personal taste.