The Darwin truly would be the perfect switcher for you Mike. Sorry for the fuzzy pic, but as you can see the balanced Darwin kit has 6 balanced inputs, two outputs and a loop out. Plenty of room for future expansion.
Unfortunately mine is not going anywhere anytime in the foreseeable future.
It may be worth your while to post at HF to see if anyone has a kit lying around, or even a finished unit. Slim chance maybe, but worth a quick inquiry.