I am not really sure that you are going to find much suitable. What it sounds like you are looking for is multiple sound cards in one package. Take a look at this:
http://www.califone.com/pdf/spec_sheets/1216USB_Spec.pdf
I have no idea if it will do what you may want it to.
Have you considered a powered usb hub with several usb sound cards plugged in? If you get cards that plug in directly, it could eliminate some cables...
That Califone device looks like what I am looking for, good catch. I run a powered hub now with three USB I/O dongles on 2 PC's. My biggest issues always seems to be Win sound management control . Get everything working then have to reboot for some reason and everything goes to hell. (gr)
Thanks MIke