There is quite a list actually, not popular since mp3 player's market is going down, even the latest iPod was at a competitive price (according to apple standards). I'd go with the samsung galaxy player 5, since it's android 5.0 and has a better batery life and more functionalities (needed or not) and a microSD extension slot. next would be walkman Z series, much shorter battery life, and only android 4.3 but the walkman sound quality.
Nevertheless it'd be better to get a good phone and ignore the sim fonctions.