i dont think you can lower either car much down, both are in demand for the most part.
the xD my friend has a 07 model. Its a neat little car. rear window visibility is not too good, its a tiny window to begin with, given that the rear seats are adjustable, with seatbelts and everything it can block a good amount of window. Car feels nice for taller people. i'm 6'0 and i don't fit nicely in some cars. the car has seen the dealership once and that was for the oil change. The radio is nice. pioneer radio, i think it does MP3 not 100% but it has ipod out with cable and everything.
I haven't been in the new rolla's i've been in the 02, but thats 2 gens behind the new ones. Both cars are great, not sure $ wise and MPG stats on the car. Since they both are going to be at the same dealership drive them back to back and back if needed. the xD price is set. so try talking the rolla price down or aleast have them throw in stuff. Go to a couple other dealerships as the toyota down the road can be 500$ cheaper and only a 20 min drive or 5 min phone call away.