How about AC's current promotion. For $250 U.S. I flew in L class (upgraded to J):
VISA Purchase 370 miles
Calgary-Montreal return: 6676 miles
double miles promo (on base miles) 5340 miles
6 segment bonus 15,000
TOTAL is 27386 miles (so far--I have several similar trips during the 199mine promotion).
Only 6676 status miles, but 27386 miles for a $250 ticket flying in business class all the way is not a bad deal! Gives me almost a free business class trip anywhere in N. America.