Has anybody seen/created a gps guided vehicle with arduino? I thought the idea of Amazon Prime air drone delivery was a pretty cool one when it first came out and I started to question whether something like that (an autonomous gps guided vehicle) could possibly be created with the Arduino microcontroller(s). Any thoughts?
Yes, someone (not me) has: https://www.youtube.com/watch?v=3-r2Jk0uA6U

I doubt it would work very well with non-flying vehicles - in the air, a 3 meter margin of error is fine, on the ground it's the difference between the sidewalk and the middle of the road.