Is it possible to connect 4 Razor IMUs with 1 single Arduino Mega 2560?

Now I have the choices between:

9 Degrees of Freedom - Sensor Stick + 4 Channel I2C Multiplexer

or

9 Degrees of Freedom - Razor IMU + RS-485 Breakout (+ two quad-AND gates and a quad-OR gates )

Does anyone have any ideas about their pros and cons? Any kinds of your experiences or references would be appreciated.