Another Merlin fate was to be used for tractor pulling. But my favourite memory is of the BOAC Argonauts opening up their four Merlins on the runway of RAF Khormaksar where my dad was stationed 1951-53. The original C54 used Twin Wasps which exhausted (I think) under the wing, making them much quieter than the Merlin stubs, but the Argonaut was 40mph faster. Passengers didn't like the noise but did like reduced time in the air -- not that it mattered much as long trips were broken up by night stops in those civilised times. Mind you, even then all eyes were on the graceful TWA Connies in their red and polished alloy livery atop a pressurised cabin.
Edited to add: just found another use for Merlins in Another Mossie Airborne thread below this one: After being sold to what proved to be an abortive project to use surplus Mosquito engines to blow air to protect fruit crops, the remains of NZ2308 ended up on a farm at Riwaka, This is the restored aircraft.