SuperCard is still around; it was always better than HyperCard anyway I think. Had full colour support and was pretty much what HyperCard should/would have been, had Apple given it the full support it deserved. Even when HyperCard finally got colour, its colour support was clunky to say the least. Don't know about HyperStudio but there are heaps of other clones around from full featured commercial ones like Runtime Revolution to opensource ones like PythonCard. I'm surprised Apple hasn't sued them for blatant plagarism actually.

And yeah, that HyperCard networking stuff is cool. I wrote an e-mail program for sending messages over a LocalTalk network in HyperCard, years before e-mail was being used to communicate at workplaces. So I'm partly to blame for the decline in face-to-face communication. :p