kflyer: do a search on PK's 772LRs. While they were built to fly ULH, they ended up flying the more humble shorter routes, primarily because, at high altitude, the fuel being uplifted severely weight restricted the load even on hops from Karachi to Europe.
And, while everybody talks of the cost savings of Twins, especially when it comes to 773ER/772LR, nobody mentions the cost of maintenance, and, even a replacement engine needs a AN124, compared to a regular freighter for most other aircraft ..