An interesting approach where Makerbot combines prefab with 3D printing on demand.
The Mixtape is an MP3 player!
The MixTape is available in two iterations. The $25 MixTape Kit, aimed at those who already own a 3D printer, includes the guts of a basic MP3 player. Simply print out the enclosure using the plans on MakerBot’s Thingiverse site, plug in the electronics, and you’re ready to upload your music.