The only thing I've seen across the nullarbor is dead roos on or near the road. Maybe an emu or two and a few crows if you count the living, Oh!!! and a feral dog (4 legged)
I've had a few close calls with Wedge tails in the NW and back blocks of WA plus roo's, goats, cattle, 1 snake and a couple largish lizard types. (goanna or monitor).
The closest near hit was a larger wedgie, wingspan of about a lane width. It wasn't going to leave it's roadkill for anything. It flew off at the last moment and I had to duck below the screen just in case. I also saw a few camels on the Marble Bar road. I gave them a plenty of room as a quad road train driver wiped his cab off a week before when he hit one.
At Karratha, on the way home from work one night a small roo did hit the LH front corner of the bike, tore off the wing cover and pushed the LH side case off. I was only doing about 80kph, my reaction was to move right. Had I hit the brakes it would have been a front wheel hit and more damage to the bike. I found the side case but the wing cover and roo were nowhere to be seen.