It would take some work, but it is possible to make one from parts bought from different places.
1) Controller (PIC?)
2) Radio receiver (for instance from phillips)
3) RDS decoder

The Radio receiver must have an "audio-out" that is compatible with the audio in to the empeg. (This was discussed here some time ago). (Where it my philips
components catalogue?)

The the PIC would have to take care of the protocols, RDS decoding, tuning of the frequency etc.

This probably wouldn't give us all the functionality of the current empeg tuner, like for instance signal strength. I don't know how accurate the frequency reading would be either.

Marius