I am not really sure if anyone needs this but Tokyo-based design company Powershovel is selling a very special kind of telephone receiver [JP], you know, the ones you can only see in old movies. The devices, probably last used in the free world in the 1980s, are called Yubz and can be connected to most Japanese handsets.
In fact, in the online shop [JP], Powershovel even claims the earpieces can be used with all existing cell phones except for Nokia and Motorola models.
The receivers cost $65 each and are available in black, yellow, pink, red, white and orange ($380 for the whole set). And they are Japan-only, which might not be too bad in this case.