In between I2C and RS485 you have transeivers like CAN and LIN and even using LM393 comparators works well.
If you multi-drop several chips you'll have to come up with a protocol, either master/slave or everyone has to detect bus clashes and retry, but what of one chip hogs the system? etc.
If you "daisy chain" you can use a token passing system whereby every chip reads the data and passes it along to the next chip with it's data added to the end, like the HDLC protocol. Daisy chaining has one flaw in that a single break on the line kills the whole network.
FWIW I'm designing a protocol for just this purpose, I'm not actively plugging it yet because it's nowhere near ready but you can have a look at http://www.bus-net.net