Ning finally got back to me on the email limit on accounts. Apparently there is none.
Quote:
"I have checked in with our engineering team and we are not aware of a limit to these messages. That is to say, if there is a limit, no one on the platform has hit it. Where there are messaging limits is how many you send out at one time. Sending to many at one time has the potential to flag the messages as spam in any email server. This is why we limit messages sent to friends to just 200."