OK, I should have asked up front, but how are you with budget? Most of what you want done is rechambering with custom ordered reamer(s), but there may be some work to the bolt face, feed path and magazine well.
ATRS in Calgary does a great job, but also builds things towards high precision and quality, they could do your rifle, but they may want to true your action or do work that will be towards a premium product with a price to match, that others would not do, not that they are unfair price vs. work.
There is Corlanes in Dawson, who could probably do this and make you happy, I would give them a call for a price. I had them put together a heavy 300WM A-bolt, I have nothing bad to say, and their communication was really helpful.
I have had Ron smith do work on a couple of rifles, his son now does the work and it is an old shop with old tooling that does really cool gain twist barrels, their prices are more competitive but I'm not sure if they'd want to do work to the bolt face and mag well, you could certainly ask.
Also nearby is Rocky mountain gun smithing, I haven't used them but would give them a call and have heard good things.
There's probably a dozen or so others that could/will be recommended but this is somewhere to start.