Do the expansion cards have an interface to the analog I/O signals, or can they only interface the I/O in the digital domain ?

I'm asking because given the flexibility and the number of channels on the H9000 platform, with its 8-in / 8-out balanced analog I/O, I could envison a digitally-controlled, all-analog signal-path mixer as a good idea for an expansion card.

It could make for a really appealing all-in-one guitar FX solution to replace my current rack, which is comprised of a Switchblade (midi-controlled anaglog-path routing mixer) along with a bunch of 1U and 2U DSP-based FX units (and/or analog pedals).

Being able to store and recall the mixer presets along with the FX algos in the same unit, in a single operation, would surely be an innovation in the field.

On top of having a 2U unit that does it all!!

Sorry but no. The expansion connector is all digital. We could design optional expansion cards with additional A to D and D to A but the 8 channels of analog I/O on the main board are not brought out to the expansion headers.