Yeah, that last part is what makes it so sad. Having 'alien' intelligences around us now could teach us a lot about how intelligence works and can work.
Ian Stewart and Jack Cohen's book "Heaven" covers this (in a way) with Neanderthal space explorers. But then there's a lot of "alienness" of thought in that. That's part of the point. This duo together specialise in the creation of credible xenobiology, for both purely fictional and proper academic purposes, up to and including xenosocieties and how they interact.
Hey, go the whole hog, check out their book "Wheelers" as well (no explicit Neanderthals, but, there's something that's very similar at one point). And for non-fiction, they've got loads of other books from the Science Of Discworld series (non-fiction discussions interspacing with Terry Pratchett's fictional sections) to ones fully in the non-fiction (if still in part speculative) area of the bookshelves. (Can you tell that I like these guys?
I could probably make a reasonable case for Computers being an alien intelligence.
I think there's a few places where I could wedge a crowbar into your terminology and crack it apart, but I
think I know what you mean, there. "Developed intelligence" Naw... (apart from the fact that it probably isn't, yet) Not "Independent intelligence" either. The fact that computers could not develop (and still
need to develop) without our own intelligence having created them[1] means that such baggage needs to be accounted for. Though I'm still waiting for some more of the events in David Brin's "Earth" to come true (having read this prior to the WWW stepping into the world, and had TBL not got there before me I might well have been in a position to use the inspiration of this book to do something similar[2]), and if that includes... Well, a certain type of intelligence, then it could be 'interesting'.
[1] Which is not to say that something could not have developed on its own.
[2] In my dreams!