An interesting idea, but difficult in execution. Ortofon went part of the way there on their early SPU cartridges building a transformer into the headshell. See the excerpt below from the Ortofon wedsite:
"Because of the very low impedance and the very low output, the first SPU cartridge, the SPU-GT, had a small transformer integrated with the cartridge units in the GM- housing, yielding about 7mVolt at 5cm/sec suitable for an MM input sockets with 50kOhm loading. "
"Because of the very low impedance and the very low output, the first SPU cartridge, the SPU-GT, had a small transformer integrated with the cartridge units in the GM- housing, yielding about 7mVolt at 5cm/sec suitable for an MM input sockets with 50kOhm loading. "