I agree with djbwow2008. If you already own a Remington 700 long action and your willing to use it as a donor action than you have everything you need. But if you don't have an action as of yet a custom may be more in line price wise. Here's a brief comparison.
You already own the Remington 700 with bottom metal and factory trigger. All you really need is to have the action blueprinted and done right ($150). Have the factory trigger tuned ($25) or replace it with a jewel ($225). Holland recoil lug ($40). This is assuming the bolt face is already a magnum and you don't need to open it up and have a sako extractor installed. This way you'll spend between $215 and $415. If you had to go out and buy a Remington 700 say an SPS you'd spend about $550. Now your up to between $765 with a factory trigger and $965 with a jewel trigger.
Now if you go with a Stiller predator your cost would be about $825 no trigger and no bottom metal but you get a good recoil lug. You'll spend another $225 for a jewel trigger and depending on which bottom metal you choose between $125 for a factory floorplate and magazine box up to $400+ for all badger stuff. So now your up to between $1175 and $1450 if you go with a Stiller predator.
The closeness is if you had to go out and buy a Remington, have it blueprinted, use a jewel trigger, Holland recoil lug and factory floorplate and magazine. Cost would be about $965
If you bought a Stiller Predator, used a jewel trigger, Remington factory floorplate and magazine it would cost you about $1175.
A difference of $210 and you've got yourself a custom action that will hold its value better than a Remington will.
There are different ways to spin the numbers depending what components you plan on using. Best thing is to figure all them out, price it out and see which ones suits your needs better.