Yeah, that's how I built the MC. It's not easy to do; drilling holes in the main board, 1.5" or so of standoffs (to get the pot shafts sticking through the bottom panel just right), and re-wiring of connectors gets pretty tight. Anyone truly adventurous can give it a try. I'm not going to write up any instructions though, as it is too easy to mess up your phonostage by attempting such. It just plain works better (mechanically) and is less risky to build the machines separately.
jh