Here's a pack of stages that I've made at one time or another. There's no stage expansion code or anything like that - just replacing almost every Brawl stage with something else.
Stage and music list at:
http://www.lakora.us/brawl/cep/libertyernie-1.0/Downloads:
With regular quality audio (288 MB)With low quality (mono 22050Hz) audio (98 MB)