"If I read that Qantas link correctly, for flights of 2001 to 4500 miles (US east coast to London) ... I could get BA business class for 45K miles, or First Class for 60K miles! (Compared to 80K/100K in the BA program today, or 100K/150K after July 1.)"
Actually, you have to plug in the RETURN mileage. So, if going through the Qantas program, you would need 100K miles for business, 125K miles for first.