I have the riflesmith get them from whomever they are used to doing business with. Brownells carries them I believe.
Kirby Allen can do it. He replaced it on my 270 AM he built.
Cost is around $65-75 I think, but with the replacement striker kits, I've never had a problem, either with factory trigger worked to 2# or replaced with a Jewel. I have no personal experience with Rifle Basix but after some research and a few questions to those that use them, it is a good and reliable trigger.
If you want to get fancy, you can contact Lex Webernick at Rifles Inc and get one of his octagon shaped bolt shrouds. They are visually appealing but serve as no superior function to the firearm over any other standard replacement kit.