Does anyone know if there is a solution like this available?
well. if there is an adapter that allows you to put Eye-Fi SD card inside whatever MF are using (like there are adapters where you can put SD card inside CF card and that adapter itself then into CF slot as a regular CF card)... Eye-Fi does not need any special firmware support from the camera, albeit some cameras do support Eye-Fi specifically (for example the firmware will not shut the camera down while Eye-Fi is transmitting the data).
been there, done that. Too slow to be usable.