jacl,
Well, I did exactly what you suggest last week and Mr Jason Lane at Irunguns was very helpful but, in the end, it looks like that importing 18 Check-Mate 1911 pistol magazines (yes, 18 magazines and all of them for me) would not be that easy - and quite a bit expensive at that. Question : how expensive ? Answer : 437.50$ CAD, excluding shipping inside Canada and GST - and the price of the magazines of course.
I should add that I am looking for very specific Check-Mate 1911 .45 ACP magazines : the ones that have the original USGI-style fully tapered feed lips for Hardball ammo only.
Assuming that it could be done, naturally, which is not that simple neither ...