I think I would have to go old school. First think I would buy is a 1874 Sharps Buffal Rifle in 45-110. There's just something about it. Then get my hands on an original Winchester '95 in 30-40 Krag. Long barrel. Never been into custom rifles, but would like to have a 300 win mag built to cut the turd from a squating coyotes arse at 800 yards. Not sure what othe rifle I could buy with the remaining 490,000 bucks.
Maybe a 50 BMG for coyote hunting. Hey, you wouldn't have even have to drag 'em out of the field.