Can't say it's perfect, but my nephew's 270 is an awesome gun. It started life as a 'Cabela's Special' and with minimal amount of accurizing, it shoots like a laser. Shooting Hornady Custom Ammo (it is 'factory' off the shelf ammo) with 130grain SST bullet, it has sufficient power to kill whitetails at 700. This year he killed one at 337 and 290. This weekend hope to stretch it out a bit farther.
Nephew's Transformed Rifle!
Annual Hunting Retreat - The Best!
Although you said, no custom work, the modifications done to nephew's rifle, is what I would recommend to anyone with a factory gun.
Although many rifles and calibers will work for your criteria, other rifles that come to mind are Remington Sendero's and Savage Long Range Hunter. In terms of caliber, give consideration to the 30cal magnums like the 300WSM and 300WinMag