+1 for this! GREAT idea.
I’m typing this at a gig where I have my H9000 which in this instance I’m just using as an interface (overkill I know), and have had to rack it with an 8 preamp expansion via ADAT, which is fine, but a card would be incredible. If I could add a headphone output to the request list, that would be even better! It’s a real faff having to bring those extra bits to a gig, and I’d LOVE to just show up with the H9000, some mics and cables rather than all the other bits which are both bulky and easy to forget.