That's an interesting idea worth checking! I don't think there is since I only see two distinct data-center ids -- but there may be one in Asia / Europe that handle more tweets from that area using one of the data center ids.
Great idea worth investigating!
I just looked at this for a set of Twitter users located in the US and it seems like their content is more or less uniformly spread across machine, and the more people tweet the more different machines serve them. So servers seem to be load-balancing.