"Be he X or be he Y" is an example of a fossil -- it's an idiom which uses an archaic grammatical structure, but it continues to be used simply because it's an idiom. This exact phrase actually comes from the classic English fairy-tale Jack and the Beanstalk: Jack, to his horror, hears the ogre saying:
Fee fi fo fum,
I smell the blood of an Englishman.
Be he alive or be he dead,
I'll grind his bones to make my bread.
Other "fossilised" examples of the subjunctive include "God save the Queen", "Allah be praised", "Thank God", "Be it as it may" and many others.
If use of the subjunctive is increasing in business correspondence, I would attribute that to the American influence.
Incidentally, it's worth noting that sports commentators are not very good barometers of contemporary English usage. They tend to create their own clichés and repeat them ad nauseum. "Over the moon" and "sick as a parrot" to describe elation and dispair respectively are two well-known examples of this.