I hear ya, it's why we've taken to stacking boards. The synthi would have been huge otherwise, as would the infinity phase. I guess you could use smd parts but then you'd put a bunch of folk off.
I'm just embarking on a eurorack modular synth project, I hate soldering smd by hand ?
Hmm, if you took all of the controls off board you might stand a chance of fitting it to a 125b but you have 6 pots and two dpdt switches so it'll be a job.
Our Spaceman PCBs are no bigger than the originals. Granted there are a few others that could be smaller.