A patent application that has only recently been published shows the potential for a new audio jack that may help reduce the size of the objects they are built into. This example explains some sort of "Pogo" mechanism in which the contacts within the audio jack:
An audio jack can allow electrical connections between an audio plug and an electronic device. The audio jack can include a series of pogo pins operative to extend into an audio jack cavity to provide conductive contacts for an audio plug placed within the audio jack. When an audio plug is inserted in the audio jack, the deflectable tips of each pogo pin can deflect and contact audio plug contact portions or regions. The end of the pogo pins opposite the deflectable tips can be coupled to an appropriate electronic device component, such as a printed circuit board, flex circuit, cable, or any other suitable component to provide a conductive path for signals between the audio plug and the electronic device.
Here, the idea is further described:
Here are some more images: