As I'm sure you know, a write off is when the vehicle repairs cost more then its value. I think you can still get it repaired but it depends on if the frame is bent (I think). Also, I think you can buy the vehicle back from the insurance company (or something like that - curbers do that sort of thing all the time) and repair it legally... But as you alluded to it depends on how much that will cost...
As an aside... A co-worker had her 2010 Rogue totaled when it was parked outside on the street at the office in November. It was a write off. Insurance impound lot guys also stole a bunch of stuff from her car and insurance didn't count half of her extras and then said she was responsible for the deductible (yeah right)... Make sure you document everything and get an exact (or as close to it as possible) independent appraisal & comparison in which to value yours (Including similar milage). You can negotiate with insurance companies. Oh and make sure you watch last weeks CBC Marketplace!!
Sorry my post doesn't answer your questions about auto body work in the US...
P