Hey Chris;
I had the same dilema last year, wanting a 6.5 Creedmoor barrel for my AIAT, and tried everything to source one here in Canada. With no luck.
After researching and reading lots of reviews, I ended up ordering a barrel from Mile High Shooting in the States. The barrel is a Bartlien and made by Dave Tooley, who does a lot of the AI stuff for them in the US. It really wasn't a terrible PIA actually. Bought the barrel, had them ship it to Prophet Rivers US partner, and Prophet River only charged me 50$ For the import, plus the shipping etc to bring it in. The girl at Prophet River, who does their importing was super helpful, and only one page form to fill out. The guys at Mile High Shooting were awesome to deal with too. Took about 3 1/2 months.
And the barrel is an absolute laser beam. Highly recommended. I did not ask them about any other calibers, but it wouldn't surprise me if they had other common short action calibers besides the 6.5 for the AT. Not sure which one you're after?
As a comparison of ordering a barrel thru dealers here in Canada, who also have to source them out of the States, I ordered a 6.5 Creedmoor factory barrel/conversion kit in for my Barrett MRAD 6 months ago thru Wolverine, and still have not received it yet. They thought it'd also be 2-3 months, and 6 months later, still no word. Not Wolverines fault at all, just them waiting for enough orders to be filled for one big shipment to be sent up I guess? Sometimes a few phone calls and to take control of the details yourself sure speeds the process up. If I had ordered that Barrett kit myself, and brought it in thru an importer, i would've had it months ago, and probably a bit cheaper too.