Cruizin,
You can build a switch barrel on any gun even a Remington 700 action, consider $300 for a match barrel + $200 to chamber, so a extra barrel may cost as much a new factory gun. Sounds like you are looking for a long range hunting rifle, not necessary to shoot in 1000 yds matches, Correct?
That said, I would consider using a prone stock, as most likely the shot will be made from prone, from a rest or bipod. Mcmillan MBR and SG&Y F-Class is the 2 that pops in my mind right now, either one will do.
Now the stock is out of the way, lets focus on the action.
First, you should decide if you want a repeater or single shot (single shot is my vote), Aluminum or SS receiver. The average cost for a trued Remington 700 is about $550, a good custom action runs about $850, to me they are worth the extra $$$, than for $1000 or so you can get in to some bad-[beeep] aluminum actions, with the budget you have in mind that should be able to narrow down your options.
As for a barrel in 6.5, I would choose a cut barrel because they do last a little longer than say a button or broached rifle and any top cut barrel maker should do.
Dan Dowling of Accuracy Gunsmithing 970-434-0525 is a top gunsmith that’s fairly close to you, just out side of Grand Junction Colorado, he is very down to earth and easy to talk to, if you are not stubborn like me he can save you a lot of money by point you in the right direction, but thats not my style.... I like to spend 2x as much and do everything twice to prove that he is right.
Now with the money you saved, put it towards a good scope and other gears that you will need to keep the rifle shooting right…. FWIW, a good scope sometimes cost as much as a custom gun.
Buzz