BTW I was looking through the IC list and related calculators on datamath.org, to see if there's interesting ones that aren't yet emulated. Long story short: a Canon Multi 8 from ebay is heading your way.
That's a weird calc! I guess the chip is just a VFD TMS1000, so that will be easy enough.
I got a TI-1031, but it has a TP0311, which datamath.org says has a one-bit serial adder. So probably too much work.