rather than bringing a limited amount of music with me in my mp3 player, I could bring a small FM tuner

Try as I might, I can't grab the logic in this one,

(1)you can get MP3 players with loads of hard disk storage, for much less than the price of all your illegal transmitting kit - and the only risk of prosecution is for a guy from Sony to turn up and handcuff you for ripping his product copyright.

(2) you can make selections as you go along with an MP3 player, instead of having to listen to a playlist/random selection at the other end of a radio wave. That strikes me as like having a plastercast on and wanting to scratch your leg!

(3) When you're laying back on your mountainside, with sweet music drifting over you, and suddenly it goes silent, you're a heck of a long way from the guy that's nicking your Empeg.

(4) A nice guy with a good idea down on projects has just floated a thread with legs for fitting a battery and charger into the spare hard disk slot to make your Empeg truly portable.