Bob,
Why am I always "A day late and a dollar short"? About two weeks ago I decided that I needed to build another one to fill the gap between my .303 British and my .450 #2 NE. It didn't take long to decide that a 9.3x74R was in order. Unfortunately, since the demise of our friend Tom, it has become impossible to find another supplier for rifle ribs. I drew up a plan for a top rib for 26" barrels and put my tool and die maker friend to work on machining it for me. Today I ordered a pair of barrels from McGowen. Now I find your post here. As I said, a day late. However, if your contact decides to build bottom ribs, similar to those that we were buying from Tom, I'd take two or three of them, in a heartbeat.
Best,
Ron.

PS: There are absolutely NO restrictions on importing parts like these into Canada. To avoid any BS on your end, I'd just enter "semi-machined parts" on the customs declaration, or keep the declared value under the "magic" $100 level. What is more brain-dead and useless than a bureaucrat ???