I think that you may be wanting a little too much from just one rifle. Unfortunately, in the real world there is rarily a free lunch. If you want a lightweight rifle that you can carry all day that will put a deer, hog or coyote down in a hurry, you really can't expect that rifle to be a tack-driving 500 yard varmint rifle. Not unless you spend lots of money putting together a super precise custom rifle and then work up a great pet load for it, but that'll cost you.

Varmint rifles of the type used for popping prairie dogs at long ranges are specialized guns, designed for varminting and target shooting alone. All of the major rifle makers offer at least one varmint/target rifle in their lineup, usually chambered in the common varmint/target calibers like .223Rem, 22-250, .243Win and .308Win. These guns generally have long heavy contoured barrels (26"+) and benchrest style stocks with wide beavertail forends and straight combs designed for shooting off a bench or bipod. They also typically weight 8-12lbs WITHOUT the scope, which is a lot of weight to tote around the deer woods. If you want a rifle for serious long range prairie dogging, this type of rifle is the one to buy.

But I think from your original post that you are more interested in a deer rifle with some varmint application. First, like I said before, don't expect that sporter weight deer rifle to print .5MOA groups. It CAN be done by some rifles with a perfectly matched handload, but 1.5MOA is a much more reasonable accuracy standard for such rifles. Also, if it were me and I were looking for a serious medium big game rifle, I wouldn't pick a light compromise caliber, but there is no need to go overboard either. What I'm basically saying is that you shouldn't compromise on a caliber like a .243 for big game if you can accurately shoot a more powerful round, but that doesn't mean that you need to run out and buy a .300 Ultra Mag either. The more I've thought about this the more I think that you're the perfect candidate for something like a 270Win, 7mm-08, .308Win or .30-06. The .270 would serve you very well without being uncomfortable to shoot during an extended shooting session. All 4 have varmint bullets available if you handload, as well as an extensive lineup if factory ammo and bullets for all forms of big game. All four have plenty of power to take almost anything in N. America, save for the greater bears (.308 and .30-06 are arguably adequate, but if I were out LOOKING to shoot an animal that can readily kill me back, I'm going better armed than that). And ammo for all, except maybe the 7mm-08, can be found all over the place for very reasonable amounts of money.

Mike