Possible to create a Walkman portable radio?

Is it possible to create a portable radio, e.g. like a Walkman and play whatever audio stream the owner wants?

Audio streams are per land parcel

So unless you stay on your own land you have no choice in what stream is played.

A portable radio would require you to be able to change other peoples audio settings - which canna be done.

You could however do an Ipod equivalent where you carry a tonn of sound files and play them when you want them ( I believe there is already such a thing out there )