Definitely unique.
The ultimate sniper rifle? First off, you're going to need about $7,500 to $10,000+. $3000+ of that is the scope. Then there's caliber. The standby it the 7.62 NATO (308 Winchester) and the long-range counterpart, the 300 Win Mag. But for the most part, people these days are stepping up to the 338 Lapua Magnum. The Lapua is an excellent choice, but expensive to shoot. You can get off-the-shelf 338's, but they're not going to shoot anywhere close to a custom rifle. You can always consider a rifle chambered in 50 BMG but that's a bit of overkill. There are also some interesting larger bore calibers- I'm working on a rifle right now in 10.3 Snipe-Tac-
A cut down 50 BMG case- at least the original caliber was. Viers has rebased it on the 408 Chey-Tac cartridge which took about 450fps out of velocity- but a more manageable caliber. The Chey-Tac is also a good caliber but has a somewhat unrealized potential.
Me- I'd go with the Lapua.
Keep in mind, proficiency at long-range marksmanship is alot like playing the piano. With years of practice, you can get pretty good at it. But ultimately a person's own natural ability will become the ceiling. And you need to have a very hands-on understanding of the weapon, ammunition and such to even get to first base. Loading your own ammo is an absolute requirement- you're wasting your time if you don't. Then it takes many, many sessions and loads of gathering of empirical data to determine what loads your rifle shoots best. But the big barrier is the actual shooting. Sniping is somewhat unlike other forms of shooting. Understanding your projectile's trajectory over its flight path is task 1. Bullets don't fly in straight lines. From the millisecond they leave the barrel, they're falling towards the ground at the exact same speed as if you held it between two fingers and let go. If you're shooting a 2800 fps 7.62 projectile 800 meters, at 100 meters the projectile's aim point is going to be about 7 feet high. Now most rifles in that caliber are going to be zeroed at 400 meters. Let's say your target is at 648 meters- you have to be able to determine that range without a rangefinder and then you have to calculate your bullet drop at that range- this is all done with what's known as a mil-dot reticle scope. It has a series of gradiations on what you might think of as crosshairs. These allow the shooter to locate the aimpoint exactly- more on mil-dot..
http://www.mil-dot.com/ Mil is short for milliradian, a metric measurement for fractional angles. Keep in mind, this is the simple stuff. Not all shoting is in a straight line. If you're 200 feet up in a tower, all bets are off- now you bring in azimuth factors that will make smoke come out of your ears. And then there are envionmental factors- wind and thermals. Just because the wind is blowing where you are, the target at 1700 meters is probably seeing something different. And if the flightpath crosses a pond or an asphalt parking lot, those thermals will move the bullet too. Experience coupled with reading environmental signs makes you a much better shooter. Oh, yeah- no calculators. You have to learn to do this stuff in your head. You can use charts, but if you're competing, you're going to get smoked by a guy that can do it in his head- there are time-on-shot elements to the scoring.
As far as the legal stuff, they're going to want to go after high-cap magazines, bayonet lugs, etc. California outright banned detachable magazines but I don't see that being in Barry's version of the AWB. Mostly imported stuff. All of it silly- since the market is filled with millions of these weapons already. All he'll do is make some guy's stuff more valuable- for a little while.