A few thoughts after visiting the Thompson website...
$4000 will build you a proper custom rifle. The website doesn't have any info as to what has been done to these weatherby rifles to accurize them. If it's a bone stock factory rifle/barrel, or just a trigger and bedding job, I'd pass without a second look. Considering they are in-stock with a 10day guarantee, I'm prone to believe they haven't done anything significant to it. Nothing against Weatherby's barrels, but they sure aren't winning any long range matches on factory barrels.
I wouldn't want the Leupold 4.5-14x40mm scope on a 1,000yrd rifle, especially without adjustable turrets. (Made me giggle a little that they misspelled turret on their site also). Some guys like hold over scopes (fixed reticle hunting), I don't. Not at that range.
I've never seen a Weatherby on a 600m or 1000yrd firing line. I'm prone to believe there's a reason for that. Not saying they aren't accurate rifles, but for that $4000 price tag, you'll get more out of a precision action than a weatherby.
So for my money, I'd build a proper custom rifle, get better results, and spend less.