Marshall:
Another choice for you would be to consider using a microcontroller such as the Cygnal C8051F020 part and simply program it with a simple data acquisition function and then interface to it via the hardware SMBus (which is I²C compatible).

Link to part...
http://www.cygnal.com/products/C8051F020.htm

This could give you a solution for 8 input channels and the part could also perform filtering, buffering, averaging, linearization, or other cool things. The part also has an 8 channel 8-bit A/D and two 12-bit D/A converters as well so it could do some rather sophisticated things.

Clearly there are probably other 8052 family parts that could also be made into a "smart peripheral" like can be done with the Cygnal part. I am just trying to show the concept. Do note however, if you are after the likes of analog performance and accuracy you are probably much better off going with the type of parts I linked in the previous posting.

Michael Karas