The two options I'd consider would be a 3-9x40 Burris Fullfield II with Ballistic Plex reticle, or the 2-10x42 Tract Toric.
The Burris costs about 1/4 as much, but they're very reliable, the optics are as good as some expensive Euro-scopes costing 4-5 times as much, and the reticle very consistent if you practice as much as you should.
The Tract comes with an built-in, easy-to-set adjustment stop on the elevation turret, and the optics are a notch higher.
What you might do is buy a Burris, then practice with it out to 500, and if it doesn't work for your needs, then buy the Tract. (There's a ready market for 3-9x40 FFIIs on the Campfire Classifieds, at about 80% of new price.) But after considerable experience am betting the Burris would work.
As another comment, from somebody who has not only hunted some but also guided, many hunters tend to think 9x or 10x isn't enough for shooting big game at 500 yards. This has not been my experience. In fact have killed plenty of much smaller varmints with 9-10x at 500--and big game out to 350 with iron sights.
