Also interesting: PunixOS, a sadly-dead project to port 4.4BSD to Motorola 68k calculators like the TI-89. Not just a Unix-alike, but a Real Unix (tm), with pre-emptive multitasking and everything.
Can you email hn@ycombinator.com so we can send you an invite to post that? Invited posts go into in the second-chance pool (described at https://news.ycombinator.com/item?id=11662380).