You bet! Transfer your Amex MR points to a Canadian Airlines account (CP), and then you can obtain BA award flights. CP generally seems to have the lowest award costs, as well.

I cannot find anything about Concorde in my awards chart, but Concorde is not included in a list of excluded BA flights. You can also go First Class, which is way, way, way, ..... way, way nicer. (You get the point.) First class tickets are generally less expensive than the Concorde tickets, so I don't think the award costs would be any higher than first. (First class, on BA, pretty much anywhere in the world, is 125,000 CP points.)

Regards,

Ken Hamer