Is it possible that commercial airliners use an EMALS or other form of electric launch?
As a start I suppose the reason of that is a particular configuration where only a short runway could be build, for instance in a highly touristic island!

EMALS uses an electromagnetic linear motor operating on a track, some studies in the 50’s have been done in Europe using the same principle not to launch the train but as a continuous powering system however they were abandoned because of compatibility between countries.

As far as power is concerned, what was theoretically possible for a train could be possible to push or to pull an aircraft, but coming to the practical application, on which part of the aircraft the pushing or the pulling force shall be applied for launching; the landing gear presently available are not designed to accept such shear forces bringing the aircraft at least to V1. 

If we consider the EMALS is just to reduce the runway length and is used just to bring an additional takeoff acceleration power, and supposing the location on the aircraft of the applied EMALS forces is solved, we get into another problem, that is the decision of the pilot at any moment before V1 to continue the takeoff or not? Should the pilot decide to cancel the flight, how to coordinate pilots decision with the EMALS disconnection, should it fail to disconnect the consequences could be terrific.

From my point of view this system requires specially designed compatible aircrafts, the economical feasibility can’t be general but specific to particular geographical configurations.

As a project why not? But economically it is hard to justify.