I'm not sure if this is helpful, but I bought CS2 through the course deal, when I started the course in Autumn 2006. Late last year, we bought a Mac (having been on PCs up to then). I contacted Adobe direct and asked them whether I could switch my software for Mac software, and they said that was fine but I had to upgrade to CS3 at the same time as CS2 was no longer available. In theory the switch from PC to Mac software was free, but I had to pay the normal upgrade fee to get CS3. But now I have the full version of CS3.

The process to make the switch was slightly tortuous (but I don't think that was any different to what anyone else would have had to go through), and I kept expecting them to come back to me and say that I couldn't do the upgrade, but they approved it and it all went through.

I know this is slightly different to what you're thinking of, but worth bearing in mind when CS4 comes out!

Carole