Jim...take a look at these pages: http://www.sover.net/~wysiwygx/MMedia.html
http://www.sover.net/~wysiwygx/MMedia2.html

..particularly Asia, MP3 Jumpgate and Pam ...note that Audacity is listed as a decent editor.

It seems full sound editing/mixer programs are just in too high a demand to be free...the really good ones are always payware.