hey Ryan,
Maxim has a couple of thermocouple interfaces (MAX6674 MAX6675) that would attach to the Arduino via SPI. Since SPI is a bus, requiring a separate chip select for each device, you could easily put a dozen or so on an Arduino as-is. With an IO expander IC you could add even more.
I've got these on my list to play with, but haven't had time yet.
-j
(TTU class of '90)