I don't think the ST version is totally dead, as the Focus RS was dead after 2002 and then magically came back. Ford is mulling over many options for global small performance cars. I met with the head of Ford Global Performance, and the father of the Focus RS. Talking with Jost and meeting with SVT, I would say chances are good that some sort of a performance model of either the Focus or Fiesta, or even both are coming in the future. My personal guess is a Fiesta ST and Focus RS, with the Focus RS being very limited and expensive.
I read in a recent interview with Jost Capito that the current Focus RS will definately not be heading stateside, though there is potential for the next generation, where I believe the North American and European cars will again be more closely related.
Regarding an ST version of the Mk7 Fiesta, it would be nice, but is made less likely by the introduction in the UK at least, of a Ford backed, Mountune Performance Pack, which takes the 1.6 Ti-VCT upto 140HP.
I wouldn't expect the North American variant to have more engine options than the European car, certainly when the Foci were both closely related the only addition was a 2.0 8v in place of the 1.4, 1.6 and 1.8 16v engines offered in Europe.