I2C ADC IC for many components located separately?
I2C (Inter-Integrated Circuit) is primarily designed for tightly coupled systems- short runs on a board- not really intended for cables and such like.  

You seem to be trying to use it for a more distributed system- in which case something like RS485, CAN, Ethernet, various Fieldbus standards, Lon, etc. (or even a wireless scheme of some kind) may be more appropriate. The wired schemes of this kind tend to use balanced terminated twisted pairs, sometimes galvanically isolated as well as shielded. 

If you find that I2C is actually suitable for your purposes you can just program small local microcontrollers as @Roger Rowland suggests. That will give you a lot of flexibility (for example, you could digitally filter and decimate signals before transmitting them to the master MCU), and you are free to determine addresses as you prefer.