About two months ago I passed a group of kids on a local trail (Piedra Blanca Trail in the Los Padres Forest) and one of them had a full sized Roland keyboard attached to his pack with bungee cords. The keyboard was in a black soft case and seriously must have been 3-4 feet long. I know nothing about keyboards but it must have been battery operated.

Glad I didn't have to share a site with them.

But no, no mp3 player for me.