Rackspace Cloud has data centers in Texas and Illinois. However, they don't let you choose (your account is assigned to one data center at the time of creation). EC2 certain offers a lot more flexibility in this regard with EC2 data center regions in California, Virginia, Ireland and Singapore. I spoke with Rackspace at Interop a few weeks ago and they told me they are working on expanding to additional data centers including an international data center very soon and offering choice.