Quintessential Player

From WWR

Quintessential Player is a free proprietary Media Player for Windows.

It is also known as QCD Player and QMP.

This venerable and possibly obsolescent player claims to be able to play MP3Pro using a now-discontinued input plugin (look for QCDmp3PRO on the forum) though whether this works with the current version of the player is uncertain. It is also able to play many strange and useless formats (and a few useful ones like FLAC) using dBpowerAMP input plugins, including (you guessed it) MP3Pro (look for in_dAPDecMgr among the input plugins).

Definitely a player for folk who like a challenge.