Really cant see BMI launching an MCO from LHR, the LON - MCO/SFB route is already very well served with VS having upto 3x daily flights from LGW, BA 1x daily, numerous charters to SFB and the connections with US, UA, AA, MP, NW, DL, FI, CO, AC etc.
NYC and BOS are prob a dead cert as no Star carriers serve this direct from LHR