Hey!
IIO suggestions are on a more expensive level.
It used to be easy to get something like a Delta 1010 (M-audio) for cheap over eBay. I mean the rackmount one (not the 1010LT). I just checked and only saw one complete from Russia, not that cheap. A lot of sellers try to only sell the rack part, which, without the pci card part is just a not so cheap big paper weight (the same goes for old digi 001).
You were looking for multi channels, right?
Oh so the delta series work with OS 9? I actually have an Delta 44 laying around somewhere, unfortunately it don't have midi though but perhaps the midi part can be solved via some USB device instead.
Multi channel is not that important- although convenient as I mainly intend to connect some old kurzweil synths and I could live with recording the output through a mixer, but of course it would be more convenient to have each stem separately to start with.
My main goal is mostly to just see if I can make a decent home studio just for fun, but to try to get as high end as I can with the least possible means as possible.
And in particular cause I have some Kurzweil K2000 and K2500 Racks laying around that I really don't use (since I got my PC3x) and it would be more fun just to have a time authentic setup I think.
I don't do music professionally (but I already have a pretty decent setup on the PC and I can't imagine this vintage gear can compete with that in anyway or form anyway, so it's mostly because I always wanted something half decent for classic mac os, but in the past such things been ridiculously expensive- and perhaps they still are in which case I guess I just forget about it.)