Driving numerous chips from 2 separate SPI connectors w/ Arduino Micro
The micro only has one SPI bus. It is SCK/MISO/MOSI. You may want a second one, but you don't have one.  You can't magic one up out of thin air.

You could emulate one in pure software (bit-banging) but it won't be anywhere near as efficient as using a real hardware one. 

Why do you feel you need to have two independent buses anyway? What are you wanting to achieve that you can't achieve with a single shared bus? That same bus can quite happily appear on multiple connectors.

One thing to note with your strategy: Ribbon connectors and SPI don't mix well together.  There is a lot of crosstalk and capacitance in a ribbon cable that high speed serial communication really doesn't like.  If I had to use ribbon cable for SPI communication for anything longer than a couple of inches I would use twice as many connections and interleave ground between each signal.  That is what the ribbon cables for later IDE drives in PCs used to get higher speed, more reliable, communication down ribbon cables.