I am not sure if you mean a transition from short haul only to long haul only or a combination of both. But I 'll give it a go with the latter, as I think they are probably more typical.
While it started out in 1947 as Malayan Airways Limited with a short hops from Kallang to Kuala Lumpur, Ipoh and Penang, and has since been through substantial changes, Singapore Airlines and Malaysia Airlines comes to mind. The airline later introduced flights to Indonesia, Vietnam, Burma (now Myanmar), North Borneo (Sabah) and Sarawak. The first transcontinental flight was to London in 1971. By then it had become Malaysia-Singapore Airlines (MSA). The following year it split into the two airlines we know today. Both SQ
offer long and short haul flights.
I don't think we can say that their model has failed but that politics got in the way of what could have been a successful single airline.
Even the example of Emirates is not completely accurate. Its first flight was to Karachi and today it serves, what? 22 - 24 routes in the Middle East and Gulf area. EK's model may be based on connecting passengers and boosting visitor numbers to Dubai, but it has successfully combined both short and long haul operations in its network.
[Edited 2012-11-27 05:28:44]