I'm reasonably sure that radio stations use a multiband compressor, and perhaps a limiter (which is a different kind of compressor than a plain old compressor).
Doug might be able to answer this more clearly, but I think they might also do some or all of this (these days) as a preprossesing step before the files go onto the radio station's hard disk in the first place.
(what, you didn't know radio stations stored their music digitally these days? Yeah, as MP2s from what I understand.)
Anyway, I agree that it would be nice to get an even-better version of the volume adjustment kernel onto the empeg, and/or a multiband compressor. There is a lot of prior art out there I think, the question is finding the right bit of code and integrating it. The question is: are you ready to do the work, Stu?