Just a quick update of progress:
I've soldered up the ramp generator and the 9 comparators on the UART-Rx pcb.
Testing that it works as it should was really easy using the excellent Analog Discovery from Digilent. Being able to watch the ramp voltage on the oscilloscope and at the same same using one digital output to re-retrigger the ramp at regular intervals and also monitor all the outputs from the comparators with the logic analyzer part of the unit was a marvelous experience.
I'm really happy that I won it in the 7400-logic contest at Dangerous Prototypes some years back. ^_^