You may be unsurprised to learn that Stross did, in Accelerando. Annoyingly, I can’t find my copy, but there’s much forking and joining of mind-states for various purposes, and one character is held liable for the actions of a mind-copy they’d never met but were deemed to be the same person.
Banks touches on it briefly in Feersum Endjinn and Hydrogen Sonata, but not to the same extent.
Ken McLeod has a lot of fun with stuff like this, both in the 2nd and 3rd books of the Fall Revolution series and in Newton’s Wake
He doesn’t really play with the multiple-copies-of-one-person interacting though, from recollection. The Stone Canal touches on it, but Accelerando thinks a lot more about the interesting possibilities of what Stross calls “Multiplicity”, where folk can freely fork many instances of themselves and potentially join the mind states up again later, etc. Revelation Space cheated its way around thinking about the issue by having alpha-levels be copy-protected. Altered Carbon has it be a rare and brief thing for anyone to be running in more than one place at once. I can see why they did this, but Stross’ stuff is more interesting because he didn’t shy away from that. I feel like this should be right up Peter Watts’ alley, but I don’t think he’s written anything on this (yet). Uploads not plausible enough for him, I guess.
For other works that you may or may not be familiar with… Lena (or MMAcevedo, which seems like a better title) is a nice short online work that does a better job. Soma is a computer game (in the “walking simulator” style) that also has some great moments, though the protagonist is annoyingly oblivious.
Yeah, I’ve got my Brit post-cyberpunk authors mixed up :D
I have read Lena and it’s one of the most chilling stories I’ve ever read. Something about the semi-factual tone (of course there’s something called red-washing to torture new uploads) and the statement of number of running uploads is really disturbing.
It also posits a possible , and to me more likely, future of human uploading - not a flowering of possibilities ala Tegmark but digital slavery.
somehow I hadn’t read Lena before, and I really like it! this is the style of fiction I’d love to write, if I had time to write fiction.