I made a new version of my launcher that supported plugins, but you still need to delete META-INF -
if that is alright with everyone, I'll post that version. Otherwise I'll keep working on it privately.
I am working on a custom Minecraft launcher.
Download it and test it and tell me if there's any bugs!!
Any suggestions for features would be appreciated.
EDIT: Here is a version for people using Java 6:
http://www.freespace.com.au/filehosting/428608
Current version: http://www.freespace.com.au/filehosting/622480
(I managed to recompile all of the launcher)
I restarted development using this version of the launcher: