that's really good idea and I agree with you. I will try to work on an extension module. When I started with euxoloti, I was thinking about a core module which will be extendable like the turing machine from music thing. The biggest problems will be first the necessary cpu resources for processing the whole I/Os and the second will be to reduce the latency.
A SPI DAC will only need 3 pinouts. Two of them are main SPI pinouts (MOSI, SCK) and the third will be further digital pin for CS/NSS. So no problem to hook up many DACs to euxoloti core.
The tides module from mutable instrument uses a DAC8552 16bit low glitch DAC and voltage shifter, but the dac8552 is a msop package. I don't know how much of you are skilled with hand soldering smd parts but it's not to difficult.
If I can organize an order at mouser or digikey, I will order one of the dac8552 and test it with the axoloti. The IC is not available in europe or very expensive (doubled price)…
An other solution can be a DAC + Mutliplexer + sample & hold circuit as rvense mentioned at the DAC thread.
But first I want to finish the core project and then develop further extension boards (CV out, Gate out etc.). By the way: The panel, core and control pcbs are shipped and will be arrive in the next two weeks.