I've been making one in Java as I too have spent countless hours messing around with pacs and textures and songs and all that jazz. I'm currently learning C and know quite a bit about assembly so maybe I'll redo it and do some research about BrawlLib. If anyone has any info on how to access and modify the common pacs such as adding textures through code, it would be greatly appreciated.
...Actually that stage manager libertyernie made is kinda what I envisioned! If you see this, send me a pm so we can chat about it. I'd love to have someone discuss BrawlLib and show me the ropes if you don't mind.
In the future I'd like to have an android app that lets you download from the vault and lets you create textures, stage names, organize pacs, edit music, etc. Like an all-in-one app for customizing brawl/project m.