Just noticed, the "dust storm" buggy >
YouTube - Burnout Paradise - Dust Storm <. That looks a bit DLC to me. Bring on more cars!! I see what you mean about the "unfinished bridge" aswell. Its just opposite the petrol station.
Theres another bit I have noticed, up at the observatory, 2 closed roads blocked off with boulders. Currently I havent been able to crash/showtime over them. sounds promising though!