i recently contacted Rythm Artists LLC ( a new charting company trained by harmonix, there website
about the whole US resident limitation and got this response:
"Hi [My Name],
Your concern has been a very commonly voiced one throughout the communities thus far. I can say with 100% certainty that you only have to be a US resident to upload content for review into the Rock Band Network. Any artist is able to partake, regardless of where the artist is actually located, as long as they can find someone to help submit it (which is where we come along).
Hopefully that answers your question
Director of Development
Rhythm Authors LLC
and there you have it, amazing win, make sure to send the website link to bands you are contacting.