I recall back in late 2006 in the SLNE estate that contiguous sims were often split up between data centers. Nantucket was located in San Francisco and Mystic was located in Dallas. Crossing that boundary was always murder. Often times you simply could not walk across, you got bounced back. It was specific complaints from the estate managers of SLNE and other large estates that lead to the policy of contigous sims all being hosted in the same data center.