Tim,
The student edition hasn't been replaced but rather a new edition has been created that is specifically for secondary schools (and the k-12 area here in the US). This is almost exactly equivalent to the University edition at the moment.
The reasoning for this is that since the two groups (university and secondary schools) are quite different in a lot of areas, so having different editions can help everyone out down the line. Clearly seperating the groups will allow us to tailor our offerings more specifically to their needs.
Regarding Schools Edition Premium, it is not currently currently available. We will be providing an Academic edition soon (same as in Creo 2.0) via a request form. What we'll be looking for in that form is that 1. You're a real teacher that we can verify and 2. that you needs exceed what is offered in the schools edition.
Please let me know if you have any questions!